CN1745421A - Optical disk unit and aberration correcting method used for this - Google Patents

Optical disk unit and aberration correcting method used for this Download PDF

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Publication number
CN1745421A
CN1745421A CNA2003801094947A CN200380109494A CN1745421A CN 1745421 A CN1745421 A CN 1745421A CN A2003801094947 A CNA2003801094947 A CN A2003801094947A CN 200380109494 A CN200380109494 A CN 200380109494A CN 1745421 A CN1745421 A CN 1745421A
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China
Prior art keywords
signal
amplitude
information recording
random signal
recording layer
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CNA2003801094947A
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Chinese (zh)
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CN1324587C (en
Inventor
户波淳一郎
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JVCKenwood Corp
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Victor Company of Japan Ltd
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    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/08—Disposition or mounting of heads or light sources relatively to record carriers
    • G11B7/09—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
    • G11B7/0945—Methods for initialising servos, start-up sequences
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/12—Heads, e.g. forming of the optical beam spot or modulation of the optical beam
    • G11B7/135—Means for guiding the beam from the source to the record carrier or from the record carrier to the detector
    • G11B7/1372—Lenses
    • G11B7/1378—Separate aberration correction lenses; Cylindrical lenses to generate astigmatism; Beam expanders
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/08—Disposition or mounting of heads or light sources relatively to record carriers
    • G11B7/09—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/12—Heads, e.g. forming of the optical beam spot or modulation of the optical beam
    • G11B7/135—Means for guiding the beam from the source to the record carrier or from the record carrier to the detector
    • G11B7/1392—Means for controlling the beam wavefront, e.g. for correction of aberration
    • G11B7/13925—Means for controlling the beam wavefront, e.g. for correction of aberration active, e.g. controlled by electrical or mechanical means
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/12—Heads, e.g. forming of the optical beam spot or modulation of the optical beam
    • G11B7/135—Means for guiding the beam from the source to the record carrier or from the record carrier to the detector
    • G11B7/1392—Means for controlling the beam wavefront, e.g. for correction of aberration
    • G11B7/13925—Means for controlling the beam wavefront, e.g. for correction of aberration active, e.g. controlled by electrical or mechanical means
    • G11B7/13927—Means for controlling the beam wavefront, e.g. for correction of aberration active, e.g. controlled by electrical or mechanical means during transducing, e.g. to correct for variation of the spherical aberration due to disc tilt or irregularities in the cover layer thickness

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  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Optical Head (AREA)
  • Optical Recording Or Reproduction (AREA)
  • Moving Of The Head For Recording And Reproducing By Optical Means (AREA)
  • Lenses (AREA)

Abstract

An optical disk unit and an aberration correcting method used for this, which require no specific pattern for correcting a spherical aberration. With an object lens (7) moved a specified distance in a first direction on an optical axis direction from a focal point position and moved the same specified distance in a second direction opposite to the first direction, a random signal, recorded in an arbitrary region on the information recording layer (12) of an optical disk (11) and having a plurality of amplitudes and a plurality of frequencies, is reproduced. A servo circuit (10) extracts, with the object lens held in respective conditions, a specific portion that is a specific amplitude or frequency portion to determine the first and second amplitudes of the specific portion, and controls an aberration correcting unit (6) so that the difference between the first and second amplitudes approaches zero.

Description

Optical disc apparatus and be used for the aberration modification method of this optical disc apparatus
Technical field
The present invention relates to the optical disc apparatus of video disc recording or regenerating information and be used for the aberration modification method of this optical disc apparatus, the thickness that particularly relates to transparency carrier that can the modifying factor CD departs from specification value and the spherical aberration of the focal point of the laser that produces writes down or optical disc apparatus of regenerating and the aberration modification method that is used for this optical disc apparatus by suitable focal point.
Background technology
In recent years, CD (Compact Disk) or DVD a plurality of various CDs such as (Digital Versatile Disk) are as the high density information recording medium and practicability.Optical system by using optical disc apparatus is carried out information record regenerating to CD to the small focal point of the information recording layer irradiating laser of CD.
Specifically, as shown in Figure 1, CD 11 is formed with information recording layer 12 along its card, uses transparency carrier 13 coverage information recording layers 12 again.With the record pit of micron dimension by circular concentric or spirality information writing information recording layer 12.Transparency carrier 13 is formed by transparent resins such as polycarbonate, is used for protecting information recording layer 12, plays the effect of keeping CD 11 self physical strength simultaneously.And, optical disc apparatus by light-conducting system record regenerating with laser aiming near the CD 11, use object lens (collector lens) 14 on the surface of information recording layer 12, to form focal point 15 then as final stage light-gathering optics.
CD 11 shown in Figure 1 is CDs of two sides record, the surface of using transparency carrier 13 coverage information recording layers 12, but under the situation of the CD that single face writes down, also can only cover transparency carrier at record side single face.
, along with the development of the high capacity of CD and densification thereupon and extremely, the numerical aperture that is used to form the object lens 14 of focal point 15 has increasing tendency recently.Numerical aperture with respect to the object lens corresponding with existing C D is 0.45, and is 0.6 corresponding to the numerical aperture of the object lens of the DVD that can carry out high density recording, but also uses the object lens of 0.8 above numerical aperture in investigation.
Under this situation, the precision of the thickness t of the transparency carrier 13 of CD 11 just has very important meaning in recording of information regeneration.That is, transparency carrier 13 has certain refractive index, is using object lens 14 to form under the situation of focal point 15, in case the thickness t of transparency carrier 13 departs from allowable value, focal point 15 will produce spherical aberration.Particularly spherical aberration is just bigger when the numerical aperture of object lens 14 increases, and the possibility that produces error in the record regenerating process will increase.For example, when the numerical aperture of object lens was 0.85, the error tolerances with the thickness t of transparency carrier 13 in general CD was taken as below several μ m.Only have current CD manufacturing technology and guarantee that such precision is quite difficult.
Fig. 2 A, Fig. 2 B represent is that optical axis with focal point 15 is the variation of the light intensity distributions at center for focus bias.Dot-and-dash line is the optical axis of laser.Fig. 2 A is the departing from allowable value with interior situation of thickness t of transparency carrier 13, Fig. 2 B be transparency carrier 13 thickness t depart from the situation that surpasses allowable value.Shown in Fig. 2 A, the thickness t of transparency carrier 13 depart from allowable value with interior situation under, beam diameter is with the light intensity distributions of focal point 15 before and after the focus point relationship change of symmetry substantially.
Relative therewith, shown in Fig. 2 B, when departing from of the thickness t of transparency carrier 13 surpassed allowable value, taking place with the optical axis was the spherical aberration of corrugated change of circular concentric at center, and the light intensity distributions of focal point 15 departs from for focus and be asymmetric variation before and after focus point.At this moment light intensity distributions becomes big for focus bias secondary lobe, and beam diameter strengthens and is in irregular tendency.
Therefore, in optical disc apparatus, surpass under the situation of allowable value, must use revise the spherical aberration of focal point 15 someway, thereby carry out record regenerating by suitable focal point 15 all the time in the departing from of thickness t of transparency carrier 13.Existing modification method as the spherical aberration of the focal point 15 that the thickness t because of the transparency carrier 13 of this CD 11 is departed from the laser that specification value produces is revised exists in the scheme that the spy opens record in the 2002-150569 communique (calling patent documentation 1 in the following text).
In patent documentation 1, record following spherical aberration correction method.That is, in the (not shown) of the boot section of CD 11, form the special pattern of 2 kinds of different hole row 107,108 of the cycle shown in the mutual arrangement plan 3A.In the example shown in Fig. 3 A, the cycle of the period ratio hole row 108 of hole row 107 is long.The regenerated signal of hole row 107,108 is the signal waveform shown in Fig. 3 B, and amplitude is big in the regenerating section of hole row 107, and amplitude is little in the regenerating section of hole row 108.
And, in patent documentation 1, also putting down in writing: the focus of focal point 15 is staggered in order, obtain the expression amplitude shown in Fig. 4 A, the 4B simultaneously, revise spherical aberration thus in the characteristic of the variation of focusing bias.
Fig. 4 A represents is resulting characteristic under the situation of deviation in allowable value of thickness t of transparency carrier 13, and Fig. 4 B represents that the deviation of the thickness t of transparency carrier 13 has surpassed resulting characteristic under the situation of allowable value.Among Fig. 4 A, Fig. 4 B, solid line is represented the amplitude variations of the regenerated signal in the macrocyclic hole row 107, and dotted line is represented the amplitude variations in the regenerated signal of short-period hole row 108.
Under the situation of Fig. 4 A that spherical aberration takes place hardly, the amplitude of the regenerated signal that is obtained by focal point 15 is in the front and back of focus point (among the figure about) symmetry roughly, relative therewith, under the situation of Fig. 4 B that has produced spherical aberration, the amplitude of regenerated signal is asymmetric in the front and back of focus point.
In Fig. 4 B, give focus deviation (defocus amount) fo1, the fo2 of peak swing (max) separately of the regenerated signal of the regenerated signal of the macrocyclic hole row 107 that solid line is represented and short-period hole row 108 that dotted line is represented surpass the spherical aberration that the margin of error of allowable value produces corresponding to the thickness t because of transparency carrier 13 to produce.Thicker and under the thin situation, give the focus deviation fo1 of the peak swing of regenerated signal, the sign-inverted of fo2 in the thickness t of transparency carrier 13 than allowable value than allowable value.Therefore, not only can differentiate the degree of spherical aberration but also the direction that light can also be differentiated aberration.Aberration shown in Fig. 4 B is made as+aberration of direction.
Therefore, if the control optical system so that focus deviation fo1, fo2 disappear (becoming minimum), just can revise spherical aberration and obtain suitable focal point 15.It more than is the spherical aberration correction method of record in the patent documentation 1.
Summary of the invention
In the patent documentation 1 of above-mentioned explanation, in the spherical aberration correction method of record, must be recorded in macrocyclic hole row 107 shown in Figure 3 and short-period hole row 108 in advance on the CD 11.Therefore, read special-purpose CD (ROM type dish) and can not make in this way for normalized.Once-type maybe can the rewriting type the situation of CD (R, RW, RAM type dish) under, optical disc apparatus must possess the generation source that produces the information signal that is used to be pre-formed macrocyclic hole row 107 and short-period hole row 108.
In addition, in the spherical aberration correction method of in patent documentation 1, putting down in writing, as mentioned above, try to achieve focus deviation fo1, the fo2 that gives the regenerated signal peak swing, so the detection of spherical aberration and correction need the suitable time owing to the focus of focal point 15 must be staggered in order.
In view of these problems, the object of the present invention is to provide a kind of optical disc apparatus of the special pattern that need not to prepare to be used to revise spherical aberration and be used for the aberration modification method of this optical disc apparatus.In addition, another object of the present invention is to provide a kind of and maybe can rewriting type CD can both revises the optical disc apparatus of spherical aberration and be used for the aberration modification method of this optical disc apparatus for reading special-purpose cd and once-type.And a further object of the present invention is to provide a kind of aberration modification method that can revise the optical disc apparatus of spherical aberration at short notice and be used for this optical disc apparatus.
For solving above-mentioned prior art problems, the invention provides a kind of optical disc apparatus that possesses the regeneration unit that the information that is recorded on the optical disc information recording layer is regenerated, it is characterized in that comprising: LASER Light Source; By the dispersion angle of adjusting the laser that sends by described LASER Light Source or the aberration correction portion that convergent angle is revised spherical aberration; Described laser is carried out optically focused forms focal point on described information recording layer object lens; Have the travel mechanism that moves described object lens along the optical axis direction of described laser, move described object lens on described information recording layer so that the focus control portion that described focal point focuses on; Detecting unit, by described focus control portion with described object lens from the focus point position along first direction only under the state of mobile ormal weight, by the random signal with a plurality of amplitudes and a plurality of cycles of described regeneration unit regenerative recording in described information recording layer arbitrary region, and extract the particular amplitude of the regenerated signal of this random signal or its interpolation signal or assign to obtain first amplitude of described specific part as the particular portion of cycle portions, simultaneously, only moving under the state of described ormal weight from the focus point position along the second direction opposite described object lens by described focus control portion with described first direction, by the random signal with a plurality of amplitudes and a plurality of cycles of described regeneration unit regenerative recording in described information recording layer arbitrary region, and extract the particular amplitude of the regenerated signal of this random signal or its interpolation signal or assign to obtain second amplitude of described specific part as the particular portion of cycle portions; And control module, control the difference that described aberration correction portion makes described first amplitude and described second amplitude and level off to zero.
Here, preferably also possess judgement and on described information recording layer, do not record should be by the random signal of described detecting unit regeneration the time whether recording on the described information recording layer to be judged to be, the random signal with a plurality of amplitudes and a plurality of cycles is recorded in the interior record cell of described information recording layer arbitrary region by the identifying unit of the random signal of described detecting unit regeneration with at described identifying unit.
Described arbitrary region is the OPC zone preferably.
The preference of described detecting unit is that described specific part is carried out the envelope detection portion that described first amplitude and second amplitude are obtained in envelope detection.
In addition, the present invention also provides a kind of optical disc apparatus that possesses the regeneration unit that the information that is recorded on the optical disc information recording layer is regenerated, and it is characterized in that comprising: LASER Light Source; By the dispersion angle of adjusting the laser that sends by described LASER Light Source or the aberration correction portion that convergent angle is revised spherical aberration; Described laser is carried out optically focused forms focal point on described information recording layer object lens; Have the travel mechanism that moves described object lens along the optical axis direction of described laser, move described object lens on described information recording layer so that the focus control portion that described focal point focuses on; Detecting unit, by described focus control portion with described object lens from the focus point position along first direction only under the state of mobile ormal weight, by the random signal with a plurality of amplitudes and a plurality of cycles of described regeneration unit regenerative recording in described information recording layer arbitrary region, and extract first particular amplitude of the regenerated signal of this random signal or its interpolation signal or as first specific part of cycle portions and second particular amplitude or as second specific part of cycle portions, obtain first difference value of the amplitude of the amplitude of described first specific part and described second specific part, simultaneously, only moving under the state of described ormal weight from the focus point position along the second direction opposite described object lens by described focus control portion with described first direction, by the random signal with a plurality of amplitudes and a plurality of cycles of described regeneration unit regenerative recording in described information recording layer arbitrary region, and extract the 3rd particular amplitude of the regenerated signal of this random signal or its interpolation signal or as the 3rd specific part of cycle portions and the 4th particular amplitude or as the 4th specific part of cycle portions, obtain second difference value of the amplitude of the amplitude of described the 3rd specific part and described the 4th specific part; And control module, control the difference that described aberration correction portion makes described first difference value and described second difference value and level off to zero.
Here, preferably also possess judgement and on described information recording layer, do not record should be by the random signal of described detecting unit regeneration the time whether recording on the described information recording layer to be judged to be, the random signal with a plurality of amplitudes and a plurality of cycles is recorded in the interior record cell of described information recording layer arbitrary region by the identifying unit of the random signal of described detecting unit regeneration with at described identifying unit.
Described arbitrary region is the OPC zone preferably.
The preference of described detecting unit has the zero cross detection unit of the zero cross point that the regenerated signal that detects described random signal or its interpolation signal and predefined zero level intersect; Detect the time interval detecting unit in the time interval between two adjacent zero cross points and according to the extraction unit that extracts described first～the 4th specific part by the described detected time interval of time interval detecting unit.
Other preferences of described detecting unit have the zero cross detection unit of the zero cross point that the regenerated signal that detects described random signal or its interpolation signal and predefined zero level intersect; Use is by regenerated signal or its interpolation signal of detected zero cross point in described zero cross detection unit and described random signal, decides local acknowledgement's judgement unit of the desired value relative with the regenerated signal of described random signal or its interpolation signal sampling spot separately according to the state transition that is determined by sweep length restriction and local response characteristic; According to the extraction unit that extracts described first～the 4th specific part by the desired value of described local acknowledgement judgement unit decision.
In addition, the present invention also provides a kind of optical disc apparatus that possesses the regeneration unit that the information that is recorded on the optical disc information recording layer is regenerated, and it is characterized in that comprising: LASER Light Source; By the dispersion angle of adjusting the laser that sends by described LASER Light Source or the aberration correction portion that convergent angle is revised spherical aberration; Described laser is carried out optically focused forms focal point on described information recording layer object lens; Have the travel mechanism that moves described object lens along the optical axis direction of described laser, move described object lens on described information recording layer so that the focus control portion that described focal point focuses on; The regenerated signal of the recorded information that is recorded on the described information recording layer being regenerated by described regeneration unit is set lifting capacity, carry out the wave shape equalization portion of wave shape equalization; Detecting unit, by described focus control portion with described object lens from the focus point position along first direction only under the state of mobile ormal weight, detection by described regeneration unit regenerated be recorded in the described information recording layer arbitrary region have the random signal in a plurality of amplitudes and a plurality of cycles the time first lifting capacity of described wave shape equalization portion, simultaneously, by described focus control portion described object lens are only being moved under the state of described ormal weight from the focus point position along the second direction opposite with described first direction, detect by described regeneration unit regenerated be recorded in the described information recording layer arbitrary region have the random signal in a plurality of amplitudes and a plurality of cycles the time second lifting capacity of described wave shape equalization portion; And control module, control the difference that described aberration correction portion makes described first lifting capacity and described second lifting capacity and level off to zero.
In addition, the invention provides a kind of aberration modification method that is used for optical disc apparatus, comprise the steps: the regeneration step that the random signal with a plurality of amplitudes and a plurality of cycles in the information recording layer arbitrary region that is recorded in CD is regenerated; Move the laser convergence that sends by LASER Light Source on described information recording layer and form the object lens of focal point along optical axis direction, make described focal point focus on focus steps on the described information recording layer; Begin along the first direction of optical axis direction only under the state of mobile ormal weight in the focus point position that described object lens are focused into from described focus steps, the described random signal of regenerating, extract the particular amplitude of the regenerated signal of this random signal or its interpolation signal or assign to obtain as the particular portion of cycle portions described specific part first amplitude first detect step; Begin to move under the state of described ormal weight in the focus point position that described object lens are focused into from described focus steps along the second direction opposite with described first direction, the described random signal of regenerating, extract the particular amplitude of the regenerated signal of this random signal or its interpolation signal or assign to obtain as the particular portion of cycle portions described specific part second amplitude second detect step; Dispersion angle or the convergent angle aberration correction portion of revising spherical aberration of control by adjusting described laser is so that the difference of described first amplitude and described second amplitude levels off to zero controlled step.
Here, preferably comprising following steps before the described regeneration step: judge whether recording on the described information recording layer and detect step and second described first and detect the determination step of the random signal that should regenerate in the step and be judged to be and do not recording on the described information recording layer when described first detects step and second and detect the random signal that should regenerate in the step, the random signal with a plurality of amplitudes and a plurality of cycles is recorded in the interior recording step of described information recording layer arbitrary region by described determination step.
Described arbitrary region is the OPC zone preferably.
Described first preference that detects the step and the second detection step is that described specific part is carried out the envelope detection step that described first and second amplitudes are obtained in envelope detection.
The present invention also provides a kind of aberration modification method that is used for optical disc apparatus, comprises the steps: the regeneration step that the random signal with a plurality of amplitudes and a plurality of cycles in the information recording layer arbitrary region that is recorded in CD is regenerated; Move the laser convergence that sends by LASER Light Source on described information recording layer and form the object lens of focal point along optical axis direction, make described focal point focus on focus steps on the described information recording layer; Begin along the first direction of optical axis direction only under the state of mobile ormal weight in the focus point position that described object lens are focused into from described focus steps, the described random signal of regenerating, extract first particular amplitude of the regenerated signal of this random signal or its interpolation signal or as first specific part of cycle portions and second particular amplitude or as second specific part of cycle portions, obtain the amplitude of described first specific part and described second specific part amplitude first difference value first detect step; Begin only to move under the state of described ormal weight in the focus point position that described object lens are focused into from described focus steps along the second direction opposite with described first direction, the described random signal of regenerating, extract the 3rd particular amplitude of the regenerated signal of this random signal or its interpolation signal or as the 3rd specific part of cycle portions and the 4th particular amplitude or as the 4th specific part of cycle portions, obtain the amplitude of described the 3rd specific part and described the 4th specific part amplitude second difference value second detect step; Dispersion angle or the convergent angle aberration correction portion of revising spherical aberration of control by adjusting described laser is so that the difference of described first difference value and described second difference value levels off to zero controlled step.
Here, preferably comprising following steps before the described regeneration step: judge whether recording on the described information recording layer and detect step and second described first and detect the determination step of the random signal that should regenerate in the step and be judged to be and do not recording on the described information recording layer when described first detects step and second and detect the random signal that should regenerate in the step, the random signal with a plurality of amplitudes and a plurality of cycles is recorded in the interior recording step of described information recording layer arbitrary region by described determination step.
Described arbitrary region is the OPC zone preferably.
Described first detects step and second preference that detects step comprises following steps: the zero cross detection step that detects the zero cross point that the regenerated signal of described random signal or its interpolation signal and predefined zero level intersect; Detect the time interval in the time interval between two adjacent zero cross points and detect step; With extract the extraction step of described first～the 4th specific part according to detect the detected time interval of step in described time interval.
Described first detects step and second other preferences that detect step comprise following steps: the zero cross detection step that detects the zero cross point that the regenerated signal of described random signal or its interpolation signal and predefined zero level intersect; Use is at regenerated signal or its interpolation signal of detected zero cross point of described zero cross detection step and described random signal, determines local acknowledgement's discriminating step of the desired value relative with the regenerated signal of described random signal or its interpolation signal sampling spot separately according to the state transition by sweep length restriction and the decision of local response characteristic; With the extraction step that extracts described first～the 4th specific part according to the desired value that determines in described local acknowledgement discriminating step.
In addition, the present invention also provides a kind of aberration modification method that is used for optical disc apparatus, comprises the steps: the regeneration step that the random signal with a plurality of amplitudes and a plurality of cycles in the information recording layer arbitrary region that is recorded in CD is regenerated; Move the laser convergence that sends by LASER Light Source on described information recording layer and form the object lens of focal point along optical axis direction, make described focal point focus on focus steps on the described information recording layer; Begin along the first direction of optical axis direction only under the state of mobile ormal weight in the focus point position that described object lens are focused into from described focus steps, in regeneration during described random signal, the regenerated signal of described random signal is set first lifting capacity and carried out the first wave shape equalization step of wave shape equalization; First of described first lifting capacity that detection is set in the first wave shape equalization step detects step; Begin only to move under the state of described ormal weight in the focus point position that described object lens are focused into from described focus steps along the second direction opposite with described first direction, in regeneration during described random signal, the regenerated signal of described random signal is set second lifting capacity and carried out the second wave shape equalization step of wave shape equalization; Second of described second lifting capacity that detection is set in the second wave shape equalization step detects step; With dispersion angle or the convergent angle aberration correction portion of revising spherical aberration of control by adjusting described laser, so that the difference of described first lifting capacity and described second lifting capacity levels off to zero controlled step.
According to optical disc apparatus of the present invention and be used for the aberration modification method of this optical disc apparatus, need not to prepare to be used to revise the special pattern of spherical aberration, just can revise spherical aberration.In addition, also can revise spherical aberration even read the CD that special-purpose CD and once-type maybe can the rewriting type.In addition, can in the short time, revise spherical aberration.
Description of drawings
Fig. 1 is CD and the sectional drawing that forms the object lens of focal point.
Fig. 2 A represents that the optical axis with focal point is the figure of the light intensity distributions at center with respect to the variation of focal shift.
Fig. 2 B represents that the optical axis with focal point is the figure of the light intensity distributions at center with respect to the variation of focal shift.
Fig. 3 A is the figure of the employed special pattern of expression prior art example.
Fig. 3 B is the figure of the regenerated signal of the employed special pattern of expression prior art example.
Fig. 4 A is the performance plot that obtains according to the state of spherical aberration in the prior art example.
Fig. 4 B is the performance plot that obtains according to the state of spherical aberration in the prior art example.
Fig. 5 is the block diagram of the one-piece construction example of first of optical disc apparatus of the present invention～the 7th embodiment.
Fig. 6 is the block diagram of the detailed structure example of first embodiment.
Fig. 7 is the planimetric map that is illustrated in an example of employed CD in the optical disc apparatus of the present invention.
Fig. 8 is the oscillogram of an example of the regenerated signal of expression first embodiment.
Fig. 9 is the process flow diagram of the aberration modification method of first embodiment.
Figure 10 A is the performance plot that obtains according to the state of spherical aberration in the first embodiment.
Figure 10 B is the performance plot that obtains according to the state of spherical aberration in the first embodiment.
Figure 10 C is the performance plot that obtains according to the state of spherical aberration in the first embodiment.
Figure 11 A is the sequential chart that is used to illustrate the aberration modification method of first embodiment.
Figure 11 B is the sequential chart that is used to illustrate the aberration modification method of first embodiment.
Figure 12 is the block diagram of the detailed structure example of second embodiment.
Figure 13 is the oscillogram that is used to illustrate the aberration modification method of second embodiment.
Figure 14 is the process flow diagram of the aberration modification method of second embodiment.
Figure 15 A is the performance plot that obtains according to the state of spherical aberration in second embodiment.
Figure 15 B is the performance plot that obtains according to the state of spherical aberration in second embodiment.
Figure 15 C is the performance plot that obtains according to the state of spherical aberration in second embodiment.
Figure 16 is the block diagram of the detailed structure example of the 3rd embodiment.
Figure 17 is the state transition diagram by sweep length restriction and response characteristic decision.
Figure 18 is the oscillogram that is used to illustrate the aberration modification method of the 3rd embodiment.
Figure 19 is the block diagram of the detailed structure example of the 4th embodiment.
Figure 20 is the block diagram of the concrete structure example of the DPLL portion 142 among Figure 19.
Figure 21 is the block diagram of the detailed structure example of the 5th embodiment.
Figure 22 A is the performance plot that obtains according to the state of spherical aberration in the 5th embodiment.
Figure 22 B is the performance plot that obtains according to the state of spherical aberration in the 5th embodiment.
Figure 22 C is the performance plot that obtains according to the state of spherical aberration in the 5th embodiment.
Figure 23 A is the performance plot that obtains according to the state of spherical aberration in the 5th embodiment.
Figure 23 B is the performance plot that obtains according to the state of spherical aberration in the 5th embodiment.
Figure 23 C is the performance plot that obtains according to the state of spherical aberration in the 5th embodiment.
Figure 24 is the block diagram of the detailed structure example of the 6th embodiment.
Figure 25 is the block diagram of the detailed structure example of the 7th embodiment.
Figure 26 is the oscillogram that is used to illustrate the aberration modification method of the 7th embodiment.
Figure 27 is the block diagram of the concrete structure example of the intersection extraction unit 175 among Figure 25.
Figure 28 is the process flow diagram that is used to illustrate the aberration modification method of the 7th embodiment.
Figure 29 A is the oscillogram that is used to illustrate the aberration modification method of the 7th embodiment.
Figure 29 B is the oscillogram that is used to illustrate the aberration modification method of the 7th embodiment.
Figure 30 is the block diagram of one-piece construction example of the 8th embodiment of optical disc apparatus of the present invention.
Figure 31 is the process flow diagram of the aberration modification method of the 8th embodiment.
Figure 32 A is the performance plot that obtains according to the state of spherical aberration in the 8th embodiment.
Figure 32 B is the performance plot that obtains according to the state of spherical aberration in the 8th embodiment.
Figure 32 C is the performance plot that obtains according to the state of spherical aberration in the 8th embodiment.
Figure 32 D is the performance plot that obtains according to the state of spherical aberration in the 8th embodiment.
Figure 32 E is the performance plot that obtains according to the state of spherical aberration in the 8th embodiment.
Figure 32 F is the performance plot that obtains according to the state of spherical aberration in the 8th embodiment.
Figure 33 A is the sequential chart that is used to illustrate the aberration modification method of the 8th embodiment.
Figure 33 B is the sequential chart that is used to illustrate the aberration modification method of the 8th embodiment.
Embodiment
Followingly optical disc apparatus of the present invention and the aberration modification method that is used for this optical disc apparatus are described with reference to accompanying drawing.Fig. 5 is the block diagram of the one-piece construction example of first of optical disc apparatus of the present invention～the 7th embodiment; Fig. 6 is the block diagram of the detailed structure example of first embodiment; Fig. 7 is the planimetric map of an example of employed CD in optical disc apparatus of the present invention; Fig. 8 is the oscillogram of an example of the regenerated signal of first embodiment; Fig. 9 is the process flow diagram of the aberration modification method of first embodiment; Figure 10 A～Figure 10 C is the performance plot that obtains according to the state of spherical aberration in the first embodiment; Figure 11 A, Figure 11 B are the sequential charts that is used to illustrate the aberration modification method of first embodiment; Figure 12 is the block diagram of the detailed structure example of second embodiment; Figure 13 is the oscillogram that is used to illustrate the aberration modification method of second embodiment; Figure 14 is the process flow diagram of the aberration modification method of second embodiment; Figure 15 A～Figure 15 C is the performance plot that obtains according to the state of spherical aberration in second embodiment; Figure 16 is the block diagram of the detailed structure example of the 3rd embodiment; Figure 17 is the state transition diagram by sweep length restriction and response characteristic decision; Figure 18 is the oscillogram that is used to illustrate the aberration modification method of the 3rd embodiment; Figure 19 is the block diagram of the detailed structure example of the 4th embodiment; Figure 20 is the block diagram of the concrete structure example of the DPLL portion 142 among Figure 19; Figure 21 is the block diagram of the detailed structure example of the 5th embodiment; Figure 22 A～Figure 22 C and Figure 23 A～Figure 23 C are the performance plots that obtains according to the state of spherical aberration in the 5th embodiment; Figure 24 is the block diagram of the detailed structure example of the 6th embodiment; Figure 25 is the block diagram of the detailed structure example of the 7th embodiment; Figure 26 is the oscillogram that is used to illustrate the aberration modification method of the 7th embodiment; Figure 27 is the block diagram of the concrete structure example of the intersection extraction unit 175 among Figure 25; Figure 28 is the process flow diagram that is used to illustrate the aberration modification method of the 7th embodiment; Figure 29 A, Figure 29 B are the oscillograms that is used to illustrate the aberration modification method of the 7th embodiment; Figure 30 is the block diagram of one-piece construction example of the 8th embodiment of optical disc apparatus of the present invention; Figure 31 is the process flow diagram of the aberration modification method of the 8th embodiment; Figure 32 A～Figure 32 F is the performance plot that obtains according to the state of spherical aberration in the 8th embodiment; Figure 33 A, Figure 33 B are the sequential charts that is used to illustrate the aberration modification method of the 8th embodiment.
＜the first embodiment 〉
Signal generating source 1 produces arbitrary signal among Fig. 5.Signal generating source 1 also can built-in memory buffer.So-called arbitrary signal can be by 0 and 1 digital signal that constitutes, only by 0 or 1 digital signal that constitutes, produce any one signals such as random signal of a plurality of values at random.As the arbitrary signal that signal generating source 1 produces, can be the recorded information (picture signal or voice signal) that is used for record on CD 11.In addition, still can be that predetermined fixed is kept at the value in the memory buffer.
As an example, the arbitrary signal of exporting from signal generating source 1 is modulated into the random signal with a plurality of amplitudes that limits according to common sweep length by 1-7pp modulation portion 2.Even will only be input under the situation of 1-7pp modulation portion 2, also be modulated into random signal and output by 0 or 1 digital signal that constitutes.Here, though carried out the 1-7pp modulation, also can be that the EFMplus modulation waits other modulator approaches.
Laser driver 3 penetrates laser (laser beam) according to the random signal driving laser light source 4 from 2 inputs of 1-7pp modulation portion from LASER Light Source 4.The laser that penetrates from LASER Light Source 4 is drawn towards object lens (condenser) 7 via spectroscope 5 and aberration correction portion 6.As an example, aberration correction portion 6 is made of concavees lens 61 and convex lens 62, and a side of concavees lens 61 and convex lens 62 or both sides can move freely along optical axis direction.By changing dispersion angle or the convergent angle that interval between concavees lens 61 and the convex lens 62 changes the laser of injecting to object lens 7, to revise the spherical aberration of focal point 15.
The structure of aberration correction portion 6 is not limited to illustrated structure, as aberration correction portion 6, also can use the zoom lens that constitutes by liquid crystal cell on as the circular concentric at center with optical axis with electrode pattern, by be applied to Control of Voltage on the electrode pattern see through liquid crystal cell light phase changing capacity device or make up the camera lens of 2 convex lens or holographic camera lens etc.In addition, in aberration correction portion 6 and object lens 7, can use collimation lens.Also can move dispersion angle or the convergent angle that collimation lens changes laser along optical axis direction.
Object lens 7 carry out optically focused with the laser of injecting, and form focal point 15 on the information recording layer 12 of CD 11.Reflected light from CD 11 is injected into spectroscope 5 via object lens 7 and aberration correction portion 6.The reflected light that spectroscope 5 is injected is injected into photodetector 8 with it.Here, adopt general spectroscope 5, but also can use polarized light beam splitter to separate reflected light effectively with 1/4 wavelength plate.
7 inscape is constituted as light picker PU from LASER Light Source 4 to object lens, and this light picker PU radially moves integratedly along CD 11.
As known in the art, photodetector 8 for example possesses the photodetector that is split into 4 parts is arranged.Regenerated signal by photodetector 8 outputs is amplified by radio-frequency amplifier 9, is input to servo circuit 10 and signal processing circuit 20 then.20 pairs of regenerated signals from radio-frequency amplifier 9 of signal processing circuit are implemented various processing outputs afterwards such as Wei Tebi decoding.The Wei Tebi decoding is by maximum likelihood decoding regenerated signal to be carried out the processing of binaryzation, and the regenerated signal that carried out binaryzation is offered not shown demodulator circuit.The signal of being handled by signal processing circuit 20 is sent to servo circuit 10, uses this signal sometimes in servo circuit 10.Servo circuit 10 possesses along optical axis direction and moves that object lens 7 carry out that the 10f of focus control portion (being shown in Fig. 6) of focus control of focal point 15 and the thickness t that is used for the transparency carrier 13 of modifying factor CD 11 depart from allowable value and the aberration Correction and Control 10a1 of portion (being shown in Fig. 6) of the spherical aberration that produces.
Though omitted concrete diagram, servo circuit 10 is also radially finely tuned the tracking Control of laser beam axis or is controlled along the main shaft that laterally moves the spindle motor 40 of controlling, make CD 11 rotations of the thick mobile integral optical pick-up device PU of the radial direction of CD 11.In addition, carry out focus control, tracking Control, laterally move control, still omitted diagram via actuator.
Control part 30 is assemblies of each one of control optical disc apparatus, control laser driver 3 or servo circuit 10.Input is illustrated in CD 11 is put into after the not shown dish loading part in control part 30, the various indicator signals that CD 11 have been encased in the detectable signal in the optical disc apparatus or imported by not shown operating portion indicator signals such as () writing down, regenerate, stop.Regenerated signal from signal processing circuit 20 also is input to control part 30.
Use Fig. 6 that the concrete structure of 10f of focus control portion and the aberration Correction and Control 10a1 of portion is described.The 10f of focus control portion possesses focus detection portion 101 and focus portion 102.The differential signal that will be divided into the multiplying signal of 4 parts the multiplying signal of first pair of angular direction of photodetector and second pair of angular direction is input to focus detection portion 101, and produces focus error signal according to this differential signal.Focus portion 102 makes object lens 7 move along optical axis direction according to the focus error signal from focus detection portion 101, focal point 15 is focused on the information recording layer 12 of CD 11.
The aberration Correction and Control 10a1 of portion possesses A/D converter 111, envelope detection portion 112, filtering portion 113 and aberration adjustment part 114.A/D converter 111 will be converted to digital signal from the regenerated signal of radio-frequency amplifier 9.The clock that is used to take a sample in A/D converter 111 both can be the clock of fixed frequency voluntarily, also can be to use PLL (phase locked loop) circuit to be synchronized with the clock of the bit rate of regenerated signal.In addition, the simulating signal that is input to A/D converter 111 has the information corresponding to bit rate.The regenerated signal that is input to A/D converter 111 is the composite signal that is split into 4 parts photodetector.The envelope (Wave crest and wave trough value) of the digital signal of input detects in envelope detection portion 112; Filtering portion 113 generates the control signal that is used for spherical aberration correction according to detected envelope.Spherical aberration is revised according to the control signal control aberration correction portion 6 that is used for spherical aberration correction in aberration adjustment part 114.
To the detailed action of envelope detection portion 112 and filtering portion 113 be described in detail in the back.
Then, describe the correction of the spherical aberration of first embodiment in detail.As shown in Figure 7; CD 11 has opening 11a at central part, and the real data that has ROM zone 11b, ingress area 11c, recording picture signal or the voice signal etc. of having stored information such as copy protection in advance along the order from interior circumferential periphery successively is the posting field 11d and the export area 11e of information signal.If CD 11 is CDs (R, RW, RAM type dish) that once-type maybe can the rewriting type, in ingress area 11c, possesses OPC zone (Optimum Power Control).So-called OPC zone is to try to write with laser in advance before CD 11 recording information signals, the zone of the optimal recording power of laser when obtaining in CD 11 writing information signal thus.
As shown in Figure 9, in the time of on CD 11 being put into the dish loading part at step S101, in step S102, judge which kind of information of in CD 11, storing.Specifically, when the detection signal on expression being put into CD 11 the dish loading part sent to control part 30, control part 30 control laser drivers 3 produced the laser of regeneration usefulness by LASER Light Source 4, and read the information of ingress area 11c.Know whether it is the CD 11 that has write which kind of recorded information by the information that reads ingress area 11c.So-called which kind of recorded information is meant operable random signal with a plurality of amplitudes and a plurality of cycles in the correction operation of spherical aberration described later.
If there is not recorded information, be set at logging mode at step S103 control part 30 so.Then, control part 30 produces record laser at step S104 control laser driver 3 by LASER Light Source 4, and the information that is used for spherical aberration correction is recorded in CD 11.
Information record in this step S104 is preferably in the OPC zone of ingress area 11c to carry out.In addition, the information that should write down is the random signal with a plurality of amplitudes and a plurality of cycles according to common sweep length restriction.By carry out the information record among the step S104 in the OPC zone, can be with the regional constriction that the information signal in the recording areas 11d (real data) is write down.In addition, the zone that record is used for the information of spherical aberration correction is the part in OPC zone, even write down the information that is used for spherical aberration correction in the OPC district, also can not exert an influence to OPC (detection of optimal recording power).
If on CD 11, write down the information that is used for spherical aberration correction at step S104, then transferred to step S105.Be judged to be under the situation that has recorded information at step S102, also transfer to step S105.At step S105, control part 30 is set at regeneration mode.And control part 30 control laser drivers 3 are by the laser of LASER Light Source 4 generation regeneration usefulness, and servo circuit 10 starts focusing function at step S106.At step S107, the regeneration of opening entry information, servo circuit 10 is in the focus point position of step S108 objective lens 7.
The regeneration of the recorded information among the step S107 is via under the situation of step S104, regeneration is in the information of step S104 record, and under situation not via step S104, then to the information of the information that writes down among the ingress area 11c or certain part of being recorded in recording areas 11d etc. arbitrarily information regenerate.Under the address administration information of the Spin Control information in when record or sector being recorded in the situation of swing (wobbling) in organizing, these information of also can regenerating.But, in any case all random signal as regeneration object.
Then, servo circuit 10 only moves object lens 7 from the focus point position along optical axis direction+α at step S109, and at this moment, the cycle takes a sample to regenerated signal in accordance with regulations.So-called along optical axis direction+direction mobile be make object lens 7 leave the direction of CD 11 and near the direction of CD 11 in the moving of any one direction.And the filtering portion 113 of servo circuit 10 (the aberration Correction and Control 10al of portion) is obtained the amplitude Ga of regenerated signal by envelope detection portion 112 detected envelopes in step S110 basis.The amplitude Ga here comes down to the peak swing of regenerated signal.
In addition, servo circuit 10 only moves object lens 7 from the focus point position along optical axis direction-α at step S111, and at this moment, the cycle takes a sample to regenerated signal in accordance with regulations.So-called along optical axis direction-the mobile of direction is to move with above-mentioned+direction is rightabout.And filtering portion 113 is obtained the amplitude Gb of regenerated signal by envelope detection portion 112 detected envelopes in step S112 basis.The amplitude Gb here comes down to the peak swing of regenerated signal.The back will be described in detail the details of amplitude Ga, Gb and ask method.
Then, filtering portion 113 obtains poor (Ga-Gb) of the peak swing of trying to achieve in each position of object lens 7 at step S113, judge the absolute value of this difference at step S114 | whether Ga-Gb| is less than or equal to the threshold value Th1 of regulation, and threshold value Th1 approaches zero setting.If | Ga-Gb| is not less than or equal to threshold value Th1, aberration adjustment part 114 is controlled aberration correction portion 6 with (Ga-Gb) as error amount at step S115 so, the dispersion angle or the convergent angle of the laser that change is injected to object lens 7 are revised the spherical aberration of focal point 15.After the processing of step S115, turn back to step S108, carry out repeatedly in the same manner.
Here, to the details of peak swing Ga, Gb and ask method to describe.As an example, the regenerated signal of step S110, S112 is a plurality of amplitudes shown in Figure 8 and the random signal of mixing of a plurality of cycle.When random signal being input to the envelope detection portion 112 of Fig. 6, as shown in Figure 8, detecting the envelope La (positive dirction) of upside and the envelope Lb (negative direction) of downside, and send to filtering portion 113.Have signal section as the detected amplitude of envelope Lb of the envelope La of this upside and downside and come down to signal with the regenerated signal equivalence of macrocyclic hole row 107 shown in Figure 3.Filtering portion 113 obtains peak swing Ga, Gb according to the envelope La of the upside of input and the envelope Lb of downside.
Here, so-called peak swing is meant the amplitude of the large amplitude signal section of the waveform that a plurality of amplitudes mix from little amplitude to large amplitude, rather than refers to the peak swing of the moment of amplitude maximum at the appointed time.
In the first embodiment, though obtain peak swing Ga, Gb, also can only obtain a side among the envelope Lb of the envelope La of upside and downside as the peak swing of plus or minus as the peak to peak value.
As Fig. 4 B is illustrated, when the thickness t of the transparency carrier 13 of CD 11 surpasses permissible range and when producing spherical aberration, obtains the peak swing of regenerated signal in the position of the focus point that departs from object lens 7.Above-mentioned peak swing Ga, Gb when producing spherical aberration, just obtain peak swing Ga, Gb in the position of the focus point that departs from object lens 7 too.Shown in Figure 10 A～Figure 10 C, with respect to the characteristic that double dot dash line is represented that is changed to of the focus deviation of peak swing.Figure 10 A situation that to be spherical aberration produced in (-) side, the amplitude of regenerated signal is in the outside of focus point (away from CD 11 sides) maximum.Figure 10 C situation that to be spherical aberration produced in (+) side, the amplitude of regenerated signal is in the inboard of focus point (near CD 11 sides) maximum.Figure 10 B is not for producing the situation of spherical aberration, and the amplitude of regenerated signal is in the focal spot maximum.
In the conventional example of Fig. 4 B explanation, the focus of focal point 15 staggered in order obtain the characteristic of expression simultaneously with respect to the amplitude variations of focus deviation, try to achieve the peak swing (max) on this characteristic, but obtain in the first embodiment, peak swing Ga, Gb of certain position that is on the characteristic of representing with double dot dash line among Figure 10 A～Figure 10 C at 2.
The positive negative indication spherical aberration of poor (Ga-Gb) of peak swing Ga, Gb is created in which side in (+) side and (-) side, absolute value in addition | and Ga-Gb| is the controlled quentity controlled variable that is used for the aberration correction.Therefore, the threshold value Th1 among the step S114 of Fig. 9 is set at absolute value | the threshold value of Ga-Gb|, here, and absolute value | the threshold value of Ga-Gb| is used for causing greatly the condition (spherical aberration drops on the condition in the permissible range) of the state that becomes Figure 10 B and sets up.As shown in Figure 9, the aberration Correction and Control 10al of portion exists | under the situation of Ga-Gb|＞Th1, as error amount, control aberration correction portion 6 with (Ga-Gb).Because the focal shift of control aberration correction portion 6 focal points 15, spherical aberration can not fall in the permissible range at once, thus carry out step S108～S115 repeatedly, up in step S114 | till Ga-Gb|≤Th1.
Above step is represented by the sequential chart of Figure 11 A, Figure 11 B.Figure 11 A represents the position switching state of object lens 7, and Figure 11 B represents to control repeatedly the peak swing Ga of the regenerated signal that causes, the variation of Gb.The Ga of Figure 11 B (1), Ga (2), Ga (3) ... and Gb (1), Gb (2), Gb (3) ... in step S110, the S112 of parantheses postfix notation Fig. 9 in detect the number of times of peak swing Ga, Gb.By Figure 11 B as can be known, the control of the spherical aberration correction of carrying out repeatedly by the aberration Correction and Control 10a1 of portion shown in Figure 9, absolute value | Ga-Gb| roughly converges to zero.
Under the constant situation of the refractive index of the transparency carrier 13 of CD 11, in advance the correction of the aberration correction portion 6 relative with error amount (Ga-Gb) is made table, if can use this table to carry out best correction, just can very promptly finish the aberration correction by once controlling.In addition, if the focal shift of revising object lens 7 simultaneously with the aberration correction makes it reach best, can form more desirable focal point 15 so.At this moment, both can alternatively carry out aberration correction and focal shift correction repeatedly and reached best, and also can carry out both sides' correction simultaneously and reach best.
More than first embodiment regeneration of explanation has the random signal in a plurality of amplitudes and a plurality of cycles, extract in the regenerated signal of this random signal particular amplitude or as the particular portion of cycle portions assign to detected amplitude Ga, Gb.Specific part in first embodiment is the amplitude part more than or equal to the specified amplitude value by 112 envelope detections of envelope detection portion, is the waveform portion that has peak swing in fact.In addition, also can not detect himself the peak swing of regenerated signal of random signal, but the peak swing of interpolation signal of regenerated signal of random signal that detected interpolation.
According to first embodiment, no matter how the condition of CD 11 can both carry out the aberration correction, make object lens 7 in the front and back of focus point position only under the state of the α of mobile equivalent, only obtain the control data of aberration correction portion 6 by the peak swing value of obtaining regenerated signal, so compare with the aberration modification method of patent documentation 1 record, can finish the aberration correction with the extremely short time.
＜the second embodiment 〉
Illustrated first embodiment of the one-piece construction of second embodiment and Fig. 5 is the same, but the aberration Correction and Control portion in the servo circuit 10 of being arranged on is with shown in Figure 6 different.It is identical with first embodiment that the random signal of regenerative recording on CD 11 revised the aberration this point.
Figure 12 represents the aberration Correction and Control 10a2 of portion of second embodiment.As shown in figure 12, the 10a2 of aberration Correction and Control portion possesses A/D converter 121, zero cross detection portion 122, crest/trough value test section 123, reversal interval test section 124, filtering portion 125 and aberration adjustment part 126.A/D converter 121 converts the regenerated signal from radio-frequency amplifier 9 to digital signal.Digital signal by A/D converter 121 outputs is sent to zero cross detection portion 122 and crest/trough value test section 123.122～filtering portion 125 of zero cross detection portion generates the error amount that is used to control aberration correction portion 6 by following program, revises spherical aberration.
Figure 14 represents the program of the aberration correction of second embodiment.The step S201 of Figure 14～S209 is identical with step S101～S109 and S111 shown in Figure 9 with S211, the explanation of clipped common segment, the program that following description of step S207 is later.Among Figure 14, in the regeneration of step S207 start record signal, servo circuit 10 is in the focus point position of step S208 objective lens 7.Then, servo circuit 10 only moves+α object lens 7 at step S209 from the focus point position along optical axis direction, at this moment, with specified period regenerated signal is taken a sample.And 122～filtering portion of zero cross detection portion of servo circuit 10 (the aberration Correction and Control 10a2 of portion) 125 obtains peak swing LA, SA at step S210, and calculates Δ Ga=(LA-SA).
In addition, at step S211, servo circuit 10 only moves-α object lens 7 from the focus point position along optical axis direction, at this moment, with specified period regenerated signal is taken a sample.And 122～filtering portion of zero cross detection portion 125 obtains peak swing LA ', SA ' at step S212, and calculates Δ Gb=(LA '-SA ').The back will be described in detail the details of peak swing LA, SA, LA ', SA ' and Δ Ga, Δ Gb and ask method.
At step S213, filtering portion 125 obtains poor (the Δ Ga-Δ Gb) of the peak swing of the regenerated signal of trying to achieve in each position of object lens 7, and judges the absolute value of this difference at step S214 | and whether Δ Ga-Δ Gb| is smaller or equal to the threshold value Th2 that stipulates.Threshold value Th2 is bordering on zero setting.If | Δ Ga-Δ Gb| also is not below or equal to the threshold value Th2 of regulation, aberration adjustment part 126 is just controlled aberration correction portion 6 with (Δ Ga-Δ Gb) as error amount at step S215, change the dispersion angle or the convergent angle of the laser of injecting to object lens 7, and revise the spherical aberration of focal point 15.After the processing of carrying out step S215, turn back to step S208, carry out repeatedly in the same manner.
Here, to the details of peak swing LA, SA, LA ', SA ' and Δ Ga, Δ Gb and ask method to describe.Figure 13 is the example by the digital signal of A/D converter 121 outputs, and white round dot and bullet are represented sampling spot.As an example, the regenerated signal among step S210, the S212 is a plurality of amplitudes shown in Figure 13 and the random signal of mixing of a plurality of cycle.
It is the zero level of threshold value that zero cross detection portion 122 has set with the specified level, obtains the poor of the regenerated signal of input and zero level, detects this moment as zero cross point when the reversal of poles of each this difference.As shown in figure 13, zero cross detection portion 122 detected zero cross points are exported as zero crossing information Z.
Represent zero crossing information Z with following (1) formula.Zero crossing information Z is the information of the timing of expression zero cross point, and the polarity of the sampling spot before and after the zero crossing information Z gives the positive and negative of regenerated signal degree of tilt.
Z＝Pole(Sn-1)∧Pole(Sn)…(1)
Here, Sn is the signal level of sampling spot, the 8th, and the EX-OR computing, Pole represents polarity with 0,1.
Zero crossing information Z is sent to crest/trough value test section 123 and reversal interval test section 124.
Crest/trough value test section 123 detects crest value Pn and the trough value Bn that is positioned at the middle regenerated signal of 2 zero cross points.The n of crest value Pn and trough value Bn increases 1 integer when whenever obtaining two zero cross points, as being represented by bullet among Figure 13, crest value is P0, P1, P2, P3 ..., the trough value is B0, B1, B2, B3 ...
Reversal interval test section 124 detects the reversal interval Tn in the time interval that is equivalent to two zero cross points.That is, begin crossing number is counted from the moment of having imported certain zero crossing information Z, the count value that detects the moment of having imported next zero crossing information is as reversal interval Tn.Being input to filtering portion 125 by crest/trough value test section 123 detected crest value Pn and trough value Bn and by reversal interval test section 124 detected reversal interval Tn.
In addition, can retrieve crest value Pn and trough value Bn with gradient method.For the sampled signal of each reversal interval Tn, obtain maximum value or minimum value by using following (2) formula computing M.In reversal interval before, obtain under the situation of crest value Pn-1, minimal value is made as trough value Bn, on the contrary, under the situation that obtains trough value Bn-1, maximum value is made as crest value Pn.
M=MAX (Sn-1, Sn) or M=MIN (Sn-1, Sn) ... (2)
Here, Sn is the signal level of sampling spot, and MAX represents to select a side big among two independent variable Sn-1, the Sn, and MIN represents to select two sides that independent variable Sn-1, Sn are medium and small.
Filtering portion 125 possesses and is used for reversal interval Tn is categorized as short period and macrocyclic table, at every turn from reversal interval test section 124 input reversal interval Tn the time, show to differentiate long period or short period according to this, crest value Pn and trough value Bn are stored in the storer (not shown) at minute growth cycle with after the short period.
And, according to the regenerated signal of certain hour amount respectively at the long period of being stored with obtain crest value Pn in the short period and the typical value of trough value Bn (for example mean value), and respectively at long period with calculate typical value poor of crest value Pn and trough value Bn in the short period.Thus, filtering portion 125 obtains the amplitude LA of macrocyclic regenerated signal and the amplitude SA of short-period regenerated signal.
In example shown in Figure 13, be that 6～8 situation is set at macrocyclic regenerated signal with reversal interval Tn, and be that 3 situation is set at short-period regenerated signal reversal interval Tn.Regenerated signal is the random signal of mixing in a plurality of amplitudes and a plurality of cycle, and in this example, regenerated signal is that reversal interval Tn serves as maximum 3～8 signals that mix with 8.Though reversal interval Tn can be macrocyclic regenerated signal with 8 only also, because it is not high that the probability of reversal interval Tn=8 takes place, so be macrocyclic regenerated signal preferably with reversal interval Tn=6～8.On the other hand, preferably short-period regenerated signal is defined as reversal interval Tn=3.Second embodiment is that the signal section of reversal interval more than or equal to regulation is extracted as macrocyclic regenerated signal, and the signal section that will have an interior reversal interval of the specialized range of reversal interval of not enough this regulation extracts as short-period regenerated signal.
In addition, in the example of Figure 13, by the crest value P1 of macrocyclic regenerated signal (Tn:6～8), P4 ... the typical value that obtains (mean value) is PL, by trough value B1, B2, B4 ... the typical value that obtains (mean value) is BL, crest value P0 by short-period regenerated signal (Tn:3), P2, P3, P5 ... the typical value that obtains (mean value) is PS, by trough value B0, B3 ... the typical value that obtains (mean value) is BS.
And filtering portion 125 uses following (3), (4) formula to obtain the amplitude LA of macrocyclic regenerated signal and the amplitude SA of short-period regenerated signal.
LA＝PL-BL……(3)
SA＝PS-BS……(4)
In second embodiment, try to achieve crest value Pn and trough value Bn both sides, obtain the amplitude LA of macrocyclic regenerated signal and the amplitude SA of short-period regenerated signal as the peak to peak value, but also can only try to achieve the side among crest value Pn and the trough value Bn, former state crest value Pn or trough value Bn are made as amplitude.In this case, LA=PL, SA=PS or LA=-BL, SA=-BS.
The advantage that is had under the situation of using crest value Pn and trough value Bn both sides is: even regenerated signal is asymmetric waveform on positive dirction and negative direction, also can not be subjected to the influence of asymmetry, can detect the amplitude LA of macrocyclic regenerated signal and the amplitude SA of short-period regenerated signal accurately, the advantage that is had under the situation of the side in only using crest value Pn and trough value Bn is: routine analyzer becomes simple.
And filtering portion 125 asks for the difference Δ Ga=(LA-SA) of the amplitude SA of the amplitude LA of macrocyclic regenerated signal and short-period regenerated signal.More than be make object lens 7 only begin from the focus point position to move along optical axis direction+during α, the poor Δ Ga that in the step S210 of Figure 14, obtains.Equally, the amplitude of the macrocyclic regenerated signal that moves object lens 7 are only begun from the focus point position along optical axis direction-obtain during α is made as LA ', the amplitude of short-period regenerated signal is made as SA ', obtains the amplitude LA ' of macrocyclic regenerated signal and the difference Δ Gb=of the amplitude SA ' of short-period regenerated signal (LA '-SA ') at step S212.
As Fig. 4 B is illustrated, when the thickness t of the transparency carrier 13 of CD 11 surpasses permissible range and when producing spherical aberration, will obtain the peak swing of regenerated signal on the position of the focus point that departs from object lens 7.The peak swing of the macrocyclic regenerated signal in second embodiment or the peak swing of short-period regenerated signal when having produced spherical aberration, will obtain the peak swing of regenerated signal too on the position of the focus point that departs from object lens 7.Shown in Figure 15 A～Figure 15 C, with respect to the characteristic that double dot dash line is represented that is changed to of the focus deviation of the peak swing of macrocyclic regenerated signal.Shown in Figure 15 A～Figure 15 C, with respect to the characteristic that is changed to single-point line expression of the focus deviation of the peak swing of short-period regenerated signal.
Figure 15 A is the situation that spherical aberration produces in (-) side, is maximum in the outside of focus point (away from CD 11 sides).Figure 15 C is the situation that spherical aberration produces in (+) side, is maximum in the inboard of focus point (near CD 11 sides).Figure 15 B is the situation that does not produce spherical aberration, is maximum in focal spot.
Difference Δ Ga produces in which side of (+) side and (-) side with the positive negative indication spherical aberration of difference Δ Gb poor (Δ Ga-Δ Gb), in addition, its absolute value | Δ Ga-Δ Gb| represents to be used for the controlled quentity controlled variable of aberration correction.By Figure 15 A～Figure 15 C as can be known, at spherical aberration Δ Ga＜Δ Gb under the situation that (-) side produces, at spherical aberration Δ Ga＞Δ Gb under the situation that (+) side produces.Do not producing under the situation of spherical aberration Δ Ga=Δ Gb.Therefore, the threshold value Th2 among the step S214 of Figure 14 is set at absolute value | the threshold value of Δ Ga-Δ Gb|, here, and absolute value | the threshold value of Δ Ga-Δ Gb| is used for causing greatly the condition of the state that becomes Figure 15 B (spherical aberration drops on the condition in the permissible range) and sets up.
As illustrated in fig. 14, | under the situation of Δ Ga-Δ Gb|＞Th2, the aberration Correction and Control 10a2 of portion is an error amount control aberration correction portion 6 with (Δ Ga-Δ Gb).Because the focal shift of control aberration correction portion 6 focal points 15, spherical aberration does not fall in the permissible range at once, thus carry out step S208～S215 repeatedly, up in step S214 | till Δ Ga-Δ Gb|≤Th2.
More than the regeneration of second embodiment of explanation has the random signal in a plurality of amplitudes and a plurality of cycles, extract macrocyclic regenerated signal and short-period regenerated signal specific part as the specific cycle portions of the regenerated signal of this random signal or the conduct in its interpolation signal, detect amplitude LA, the LA ' of macrocyclic regenerated signal and the difference Δ Ga=(LA-SA) of amplitude SA, the SA ' of short-period regenerated signal then, Δ Gb=(LA '-SA ').So-called macrocyclic regenerated signal is the signal section more than or equal to period 1 (for example more than or equal to reversal interval 6), and so-called short-period regenerated signal is not enough period 1 and the signal section of second round (for example reversal interval 3) in specialized range.
According to second embodiment, no matter how the condition of CD 11 can both carry out the aberration correction, make object lens 7 in the front and back of focus point position only under the state of the α of mobile equivalent, the difference Δ Ga=(LA-SA) of amplitude LA, the LA ' by obtaining macrocyclic regenerated signal and amplitude SA, the SA ' of short-period regenerated signal only, Δ Gb=(LA '-SA ') obtains the control data of aberration correction portion 6, so, compare with the aberration modification method of record in the patent documentation 1, can finish the aberration correction with the extremely short time.
In first embodiment and second embodiment, comparison diagram 10A～Figure 10 C and Figure 15 A～Figure 15 C as can be known, | Δ Ga-Δ Gb| is greater than | Ga-Gb|, with respect to focus deviation | the rate of change of Δ Ga-Δ Gb| is greater than | the rate of change of Ga-Gb|.Therefore, according to second embodiment, can carry out high-precision aberration correction more efficiently than first embodiment.
＜the three embodiment 〉
First embodiment of the one-piece construction of the 3rd embodiment and Fig. 5 explanation is identical, but aberration Correction and Control portion and Fig. 6, shown in Figure 12 different.The 3rd embodiment is partly to use the circuit in the signal processing circuit 20 to constitute aberration Correction and Control portion.Identical in the random signal correction aberration this point of regenerative recording on CD 11 with first, second embodiment.
That Figure 16 represents is the aberration Correction and Control 10a3 of portion of the 3rd embodiment.As shown in figure 16, the 10a3 of aberration Correction and Control portion possesses A/D converter 131, zero cross detection portion 132, interpolation portion 133, local acknowledgement (PR) judegment part 134, filtering portion 135 and aberration adjustment part 136.Be arranged on part in the signal processing circuit 20 from the part of A/D converter 131 to PR judegment parts 134, filtering portion 135 and aberration adjustment part 136 are arranged in the servo circuit 10.Viterbi decoder 200 uses maximum likelihood decoding that the input signal from PR judegment part 134 is carried out 2 values and output.
A/D converter 131 converts the regenerated signal from radio-frequency amplifier 9 to digital signal.The clock that is used for A/D converter 131 samplings is to use the synchronous clock of bit rate of PLL circuit and regenerated signal.Digital signal by A/D converter 131 outputs is sent to zero cross detection portion 132 and interpolation portion 133.132～filtering portion 135 of zero cross detection portion generates the error amount that is used to control aberration correction portion 6 by following program, and revises spherical aberration.
Among Figure 16, zero crossing information Z detects by the program identical with second embodiment in zero cross detection portion 132, and sends it to PR judegment part 134.Interpolation portion 133 makes regenerated signal postpone 180 °, the sampled signal of a front and current sampled signal is averaged, and average data (interpolation signal) is sent to PR judegment part 134 and filtering portion 135.PR judegment part 134 uses the zero crossing information Z and the average data of input, differentiates the desired value that sampling spot should be obtained according to the sweep length restriction (RLL) of regenerated signal with by the state transition of PR characteristic decision.
Here, the PR characteristic is described.With PR (a, b, b, when characteristic a) gave individual waves and carries out equilibrium, its equalized waveform got 0 under the situation of RLL (1,7), a, a+b, 2a, 2b, a+2b, 7 values of 2a+2b.When being input to these 7 values in the Viterbi decoder 200, the constraint that is subjected to signal in the past to the input value and the regenerated signal (output valve) after the PR equilibrium of Viterbi decoder 200 input.Can be not double during above situation in " 1 " of using input signal according to RLL (1,7), input value/output valve just can be represented by state transition diagram shown in Figure 17.S0～S5 of Figure 17 represents the state by the decision of before output valve.
Among Figure 17, for example when being in state S2, if input value is 1, perhaps output valve becomes a+2b and moves to state S3, and perhaps output valve becomes 2b and moves to state S4.
, represent to have detected zero cross point when zero crossing information Z is " 1 ", this situation occurs in the transition process of state S1 → S2 among Figure 17 or S4 → S5.At this moment, state S2, S3 among Figure 17, S4 follow on the occasion of the path (turn under the situation of a+b=0 a+2b in standard, and state S5, S0, S1 follow the path of negative value (turns in standard under the situation of a+b=0 2a+2b, some among the 2b),, 0, a, some among the 2a).Therefore, the value before or after the reference zero cross point, can differentiate positive path still is negative path.In addition, in the state transition diagram of Figure 17, the value except a+b, promptly when being not zero cross point, zero crossing information Z is " 0 ".
If know interval (if promptly knowing from state S2 to state S5 or transport number) from state S5 to state S2 from certain zero cross point to next zero cross point, will determine the path, each sampling spot is determined the data value that should obtain.
By the state transition diagram of Figure 17 as can be known, do not have the situation of continuous output 2 zero crossing information Z " 1 ", in addition, RLL (1, under situation X), between adjacent zero cross point, have a zero crossing information Z " 0 " at least.When zero crossing information Z has carried out the variation of " 1 " → " 0 " → " 1 ", the migration of state S1 → S2 → S4 → S5 or the migration of state S4 → S5 → S1 → S2 have been produced.In addition, RLL (2, under situation X), between adjacent zero cross point, have two zero crossing information Z " 0 " at least.
PR judegment part 134 determines the desired value at each sampling spot place according to above PR characteristic.For example, for PR (a, b, b, a) characteristic, when the minimum sweep length of regenerated signal is restricted to 2 (minimum reversal interval is 3), the path that does not have S2 → S4 and S5 → S1 among Figure 17, becoming only is state transition around the path, because the zero crossing state is S2 and S5, if, just can determine the desired value at each sampling spot place so know the polarity of sampling spot and the interval between zero cross point.In addition, when the minimum sweep length of regenerated signal is restricted to 1 (minimum reversal interval is 2), become the state transition of Figure 17, the state of zero crossing also is S2 and S5 in this case, so can similarly determine the desired value at each sampling spot place.
That is, PR judegment part 134 is according to the polarity of the zero crossing information Z of zero cross detection portion 132, sampling spot and the average data of interpolation portion 133 outputs, generates this average data and whether be the differentiation data corresponding to the data of certain desired value.
And filtering portion 135 uses the differentiation data that obtain from PR judegment part 134, and the average data of interpolation portion 133 outputs is distinguished to each desired value.But because do not use zero level, so be omitted.
Specifically, as shown in figure 18, corresponding to the desired value 2a+2b that obtains from PR judegment part 134, a+2b, a, 0, each average data is distinguished by filtering portion 135, and each data group that distinguishes is obtained its average value P L, PS, BS, BL.Among Figure 18, the average data group that white round dot is represented belongs to desired value 2a+2b, 0; The average data group that bullet is represented belongs to desired value a+2b, a.
The average data group who belongs to desired value 2a+2b gets the value approaching with the crest value of macrocyclic signal, the average data group who belongs to desired value 0 gets the value approaching with the trough value of macrocyclic signal, the average data group who belongs to desired value a+2b gets the value approaching with the crest value of short-period signal, and the average data group who belongs to desired value a gets the value approaching with the trough value of macrocyclic signal.
Therefore, average value P L, BL are respectively the crest value that is similar to macrocyclic signal and the value of trough value, and average value P S, BS are respectively the crest value that is similar to short-period signal and the value of trough value.
In addition, the same with second embodiment, filtering portion 135 obtains the amplitude SA of the amplitude LA of macrocyclic regenerated signal and short-period regenerated signal as the peak to peak value by above-mentioned (3), (4) formula.Amplitude LA, SA also can be with crest value or trough value former state ground as amplitudes.
The same with second embodiment, as Figure 14 explanation like that, the difference Δ Ga=(LA-SA) of the amplitude SA of the amplitude LA that obtains at the macrocyclic regenerated signal that makes object lens 7 only move from focal position along optical axis direction+obtain during α of filtering portion 135 and short-period regenerated signal and at the difference Δ Gb=of the amplitude SA ' of the amplitude LA ' of the macrocyclic regenerated signal that makes object lens 7 only move from focal position along optical axis direction-obtain during α and short-period regenerated signal (LA '-SA ').Aberration adjustment part 136 is an error amount with (Δ Ga-Δ Gb), and control aberration correction portion 6 changes the dispersion angle of the laser of injecting to object lens 7 or convergent angle, revises the spherical aberration of focal point 15.
More than the regeneration of the 3rd embodiment of explanation has the random signal in a plurality of amplitudes and a plurality of cycles, macrocyclic regenerated signal (interpolation signal) and short-period regenerated signal (interpolation signal) are extracted as the specific part as specific cycle portions in the interpolation signal of the regenerated signal of this random signal, detect difference Δ Ga=(LA-SA), the Δ Gb=(LA '-SA ') of amplitude SA, the SA ' of amplitude LA, the LA ' of macrocyclic regenerated signal and short-period regenerated signal then.So-called macrocyclic regenerated signal is (for example to be included in desired value 2a+2b more than or equal to the period 1, average data group in 0) signal section, so-called short-period regenerated signal is not enough period 1 and the signal section of second round (for example being included in desired value a+2b, the average data group in a) in specialized range.
According to the 3rd embodiment, no matter how the condition of CD 11 can both revise aberration, only only difference Δ Ga=(LA-SA), the Δ Gb=of amplitude SA, the SA ' of amplitude LA, the LA ' by obtaining macrocyclic regenerated signal and short-period regenerated signal (LA '-SA ') obtain the control data of aberration correction portion 6 under the state of the α of mobile equivalent before and after the focus point position making object lens 7, therefore compare with the aberration modification method of patent documentation 1 record, can finish the aberration correction with the extremely short time.
, in the 3rd embodiment,, carry out PR by 134 pairs of these interpolation signals of PR judegment part and differentiate, but also can directly carry out the PR differentiation according to the sampling method of A/D converter 131 to the regenerated signal of random signal by interpolation portion 133 interpolation regenerated signals.This also is identical in other embodiments described later.
＜the four embodiment 〉
Illustrated first embodiment of the one-piece construction of the 4th embodiment and Fig. 5 is identical, but aberration Correction and Control portion and Fig. 6, Figure 12, shown in Figure 16 different.The 4th embodiment also is partly to use the circuit in the signal processing circuit 20 to constitute aberration Correction and Control portion.Identical in the random signal correction aberration this point of regenerative recording on CD 11 with first～the 3rd embodiment.
That Figure 19 represents is the aberration Correction and Control 10a4 of portion of the 4th embodiment, as shown in figure 19, the 10a4 of aberration Correction and Control portion possesses A/D converter 141, DPLL (digital phase-locked loop) portion 142, local acknowledgement (PR) judegment part 143, filtering portion 144 and aberration adjustment part 145.Be arranged in the signal processing circuit 20 from the part of A/D converter 141 to PR judegment parts 143, filtering portion 144 and aberration adjustment part 145 are arranged in the servo circuit 10.
A/D converter 141 moves by the self-operating clock of fixed cycle, to taking a sample from the regenerated signal of radio-frequency amplifier 9, and its sampled signal is sent to DPLL portion 142.DPLL portion 142 possesses the PLL function of oneself finishing, and the regenerated signal of being imported by self interpolation also is generated as the signal of resampling, and extracts phase error simultaneously by it being fed back the timing of controlling interpolation.
DPLL portion 142 constitutes as illustrated in fig. 20 like that.Resample interpolation portion 1421 according to by the timing signal of timing generating unit 1424 outputs to resampling from the sampled signal of A/D converter 141, simultaneously the sampled signal of a front and current sampled signal are averaged, the signal of resampling after it is handled as interpolation sends to phase shift test section 1422.
When the resample signal of phase shift test section 1422 after interpolation is handled sent to filtering portion 144, detected phase misplaced and the phase shift signal is sent to ring-like wave filter 1423.Phase shift test section 1422 is also parallel when carrying out the phase shift detection to carry out the detection of zero crossing, and Z sends to filtering portion 144 zero crossing information.Ring-like wave filter 1423 extracts the lower frequency region part of phase error signal, sends to regularly generating unit 1424 as the dislocation level information.Regularly generating unit 1424 generates above-mentioned timing signal according to the dislocation level information of being imported.
Therefore, the signal of resampling by this DPLL portion 142 can obtain with correct timing interpolation using the output of the A/D converter 141 that the clock of self-operating moves can also obtain zero crossing information Z from phase error detection portion 1422.
Be sent to PR judegment part 143 from resample signal and the zero crossing information Z of DPLL portion 142 output.The same with the 3rd embodiment, PR judegment part 143 uses zero crossing information Z and the signal of resampling is made (RLL) and differentiated desired value by the state transition of PR characteristic decision according to being extended the deadline by the scanning of regenerated signal.
The signal and be input to filtering portion 144 of resampling from the differentiation data of the desired value of PR judegment part 143 outputs from DPLL portion 142 output, according to the program identical, obtain difference Δ Ga=(LA-SA), the Δ Gb=(LA '-SA ') of amplitude SA, the SA ' of amplitude LA, the LA ' of macrocyclic regenerated signal and short-period regenerated signal with the 3rd embodiment.And aberration adjustment part 145 is an error amount control aberration correction portion 6 with (Δ Ga-Δ Gb), makes the dispersion angle of the laser of injecting to object lens 7 or convergent angle change the spherical aberration of revising focal point 15.
The 4th embodiment is the same with the 3rd embodiment, regeneration has the random signal in a plurality of amplitudes and a plurality of cycles, extract macrocyclic regenerated signal and short-period regenerated signal specific part, detect difference Δ Ga=(LA-SA), the Δ Gb=(LA '-SA ') of amplitude SA, the SA ' of amplitude LA, the LA ' of macrocyclic regenerated signal and short-period regenerated signal then as the specific cycle portions of the regenerated signal of this random signal or the conduct in its interpolation signal.So-called macrocyclic regenerated signal is the signal section more than or equal to the period 1; So-called short-period regenerated signal is not enough period 1 and the signal section of second round in specialized range.
According to the 4th embodiment, no matter the condition of CD 11 how, can both revise aberration, make object lens 7 before and after the focus point position only under the state of the α of mobile equivalent, only difference Δ Ga=(LA-SA), the Δ Gb=of amplitude SA, the SA ' of amplitude LA, the LA ' by obtaining macrocyclic regenerated signal and short-period regenerated signal (LA '-SA ') obtain the control data of aberration correction portion 6, therefore compare with the aberration modification method of patent documentation 1 record, can finish the aberration correction with the extremely short time.
＜the five embodiment 〉
First embodiment of the one-piece construction of the 5th embodiment and Fig. 5 explanation is the same, but aberration Correction and Control portion and Fig. 6, Figure 12, Figure 16, shown in Figure 19 different.The 5th embodiment also is partly to adopt the circuit in the signal processing circuit 20 to constitute aberration Correction and Control portion.Identical with first～the 4th embodiment on the random signal correction aberration this point on the CD 11 at regenerative recording.
That Figure 21 represents is the aberration Correction and Control 10a5 of portion of the 5th embodiment.As shown in figure 21, the 10a5 of aberration Correction and Control portion possesses A/D converter 151, DPLL portion 152, local acknowledgement (PR) differentiation balanced portion 153, filtering portion 154 and aberration adjustment part 155.The part of differentiating balanced portion 153 from A/D converter 151 to PR is arranged in the signal processing circuit 20, and filtering portion 154 and aberration adjustment part 155 are arranged in the servo circuit 10.
The 5th embodiment is characterised in that to be differentiated balanced portion 153 by PR to carry out PR according to resample signal and zero crossing information Z by 152 inputs of DPLL portion balanced and differentiate according to the hypothesis of being carried out desired value by the state transition of sweep length limit decision, in addition, whether also select the error relative with the desired value of the signal of resampling of reality carried out equilibrium.
As Figure 17, Figure 18 of the 3rd embodiment were illustrated, state S2 and S5 were equivalent to zero point, and 2a+2b is the maximum target value of positive side, and 0 is the maximum target value of minus side.Do not carry out the error equilibrium for the signal of resampling that relates to these desired values, only a+2b, a+b, a as other desired values are carried out the error equilibrium.Like this, just the short-period signal of resampling that relates to desired value a+2b, a+b, a is carried out wave shape equalization and handle, particularly suppress from crosstalking that the signal of long period when the variation of short period asked.Therefore, though relate to desired value 2a+2b, 0 the macrocyclic signal of resampling changes according to input signal, the short-period signal of resampling that relates to other desired values a+2b, a+b, a is become approaching with steady state value substantially value by equilibrium.
Specifically, the signal of being represented by bullet of resampling (near the signal the zero crossing) of resampling signal and belonging to desired value a+b that belongs to desired value a+2b, a shown in Figure 180 is by equilibrium treatment and constant substantially, only relates to desired value 2a+2b, 0 the actual amplitude of signal reflection of resampling.
Therefore, when filtering portion 154 handles, the crest value PL of macrocyclic signal and trough value BL are not subjected to the influence of crosstalking between signal, can detect the long period signal amplitude LA (=PL-BL), and can correctly obtain amplitude LA for the long period signal of the focus deviation of object lens 7.In the 5th embodiment, be equivalent to short-period signal amplitude SA (=PS-BS) be roughly steady state value.
In the 5th embodiment, shown in Figure 22 A～Figure 22 C, relative with the focus deviation of the peak swing of the macrocyclic regenerated signal represented characteristic of double dot dash line that is changed to, relative with the focus deviation of the peak swing of the short-period regenerated signal represented characteristic of single-point line that is changed to.Therefore, by the Δ Ga=(LA-SA) that filtering portion 154 obtains, Δ Gb=(LA '-SA ') mainly only reflects the amplitude LA of macrocyclic regenerated signal, the variation of LA '.
Because amplitude SA, the SA ' of short-period regenerated signal are same value, so shown in Figure 23 A～Figure 23 C, also can establish Δ Ga=LA, Δ Gb=LA '.
The regeneration of the 5th embodiment has the random signal in a plurality of amplitudes and a plurality of cycles, extract macrocyclic regenerated signal and short-period regenerated signal specific part, detect amplitude LA, the LA ' of macrocyclic regenerated signal and difference Δ Ga=(LA-SA), the Δ Gb=of amplitude SA, the SA ' of short-period regenerated signal (LA '-SA ') then as the specific cycle portions of the regenerated signal of this random signal or the conduct in its interpolation signal.But amplitude SA, the SA ' of short-period regenerated signal is not amplitude itself, but undertaken being converted to constant substantially value after the equilibrium by the processing that PR differentiates in the balanced portion 153.
In addition, establishing Δ Ga=LA, under the situation of Δ Gb=LA ', the 5th embodiment extracts the specific part of macrocyclic regenerated signal as the specific cycle portions of the conduct in the regenerated signal of random signal.
According to the 5th embodiment, no matter how the condition of CD 11 can both revise aberration, make object lens 7 before and after the focus point position only under the state of the α of mobile equivalent, only difference Δ Ga=(LA-SA), the Δ Gb=of amplitude LA, the LA ' by obtaining macrocyclic regenerated signal and amplitude SA, the SA ' of short-period regenerated signal (LA '-SA ') obtain the control data of aberration correction portion 6, therefore compare with the aberration modification method of patent documentation 1 record, can finish the aberration correction with the extremely short time.
＜the six embodiment 〉
The 6th embodiment is the variation of the 5th embodiment.That Figure 24 represents is the aberration Correction and Control 10a6 of portion of the 6th embodiment.As shown in figure 24, the 10a6 of aberration Correction and Control portion possesses A/D converter 161, zero cross detection portion 162, local acknowledgement (PR) differentiation balanced portion 163, filtering portion 164 and aberration adjustment part 165.The part of differentiating balanced portion 163 from A/D converter 161 to PR is arranged in the signal processing circuit 20, and filtering portion 164 and aberration adjustment part 165 are arranged in the servo circuit 10.
The 5th embodiment uses DPLL portion 152 interpolation of resampling as mentioned above, but the 6th embodiment is not resampled.Among Figure 24, A/D converter 161 uses the bit rate of the regenerated signal of PLL circuit and input synchronously regenerated signal to be taken a sample, and this sampled signal is sent to zero cross detection portion 162 and PR differentiates balanced portion 163.PR differentiates balanced portion 163, and to use zero crossing information Z from zero cross detection portion 162 to carry out PR balanced and differentiate according to the hypothesis of being carried out desired value by the state transition of sweep length limit decision.
In the 6th embodiment, no matter how the condition of CD 11 can both revise aberration, compare with the aberration modification method of patent documentation 1 record, also can finish the aberration correction with the extremely short time.
＜the seven embodiment 〉
The one-piece construction of the 7th embodiment is identical with first embodiment that Fig. 5 illustrated, but aberration Correction and Control portion and Fig. 6, Figure 12, Figure 16, Figure 19, Figure 21, aberration Correction and Control portion shown in Figure 24 are different.It is identical to revise aberration this point and first～the 6th embodiment in the random signal of regenerative recording on CD 11.
That Figure 25 represents is the aberration Correction and Control 10a7 of portion of the 7th embodiment, and the aberration Correction and Control 10a7 of portion is set in the servo circuit 10.As shown in figure 25, the 10a7 of aberration Correction and Control portion possesses A/D converter 171, ATC (Automatic Threshold Level Control) circuit 172, agc circuit 173, envelope detection portion 177, filtering portion 178 and aberration adjustment part 179.Agc circuit 173 comprises gain control circuit 174, intersection extraction unit 175 and error-detecting portion 176.
Among Figure 25, A/D converter 171 is taken a sample to the regenerated signal of being imported by the self-operating clock of fixed frequency, and this sampled signal is sent to ATC circuit 172.The centered level (DC level) of 172 pairs of sampled signals of being imported of ATC circuit is controlled and is made it consistent with predefined optimal threshold, sends to agc circuit 173 then.Gain control is carried out in the output of 173 pairs of ATC circuit 172 of agc circuit so that short reversal interval signal becomes certain size, sends to envelope detection portion 177 then.
The gain control circuit 174 of agc circuit 173 sends to envelope detection portion 177 then and intersects extraction unit 175 according to by error-detecting portion 176 detected gain error signals gain control being carried out in the output of ATC circuit 172.Error-detecting portion 176 comes the output gain error signal according to the output of intersection extraction unit 175.The concrete formation and the action specification of intersection extraction unit 175 are as follows.
As shown in figure 26, intersecting threshold value Th10, level that extraction unit 175 sets in advance intermediate level greater than the threshold value Th11 of threshold value Th10 and the level threshold value Th12 less than threshold value Th10, and the threshold value Th10 of above-mentioned intermediate level is set near the centered level of the amplitude Q in the minimum reversal interval of regenerated signal Sr.The level difference of threshold value Th10 and threshold value Th11 and threshold value Th10 and threshold value Th12 level difference are set to such an extent that all equal P.Level difference P is set to less than the amplitude Q in the minimum reversal interval.Therefore, any one of these three threshold value Th10, Th11, Th12 all must be represented correct zero crossing value.In the example of Figure 26, threshold value Th10 is the zero crossing value.
Number of times when intersecting extraction unit 175 accumulation being calculated regenerated signal Sr and crossed threshold value Th10, threshold value Th11, threshold value Th12 respectively individually respectively, if some in three accumulated values reached predefined setting value, will repeat same action once more after three whole zero clearings of accumulated value.
The sort of formation shown in intersection extraction unit 175 image patterns 27.Among Figure 27, the regenerated signal Sr by gain control circuit 174 outputs is input to crossing detector 1751～ 1753.In crossing detector 1751,1752,1753, be set with threshold value Th10, Th11, Th12 respectively, output was counted when regenerated signal Sr crossed threshold value Th10, Th11, Th12 at every turn accumulated value (intersection count value) C0, C1, C2.Intersection count value C0, C1, C2 by crossing detector 1751,1752,1753 outputs are imported into comparer 1754,1755,1756.Comparer 1754～1756 compares the intersection count value C0～C2 that imported and general setting value, comparative result is input to the OR circuit 1757 of 3 inputs.
The setting value that inputs to comparer 1754～1756 be set to respect to minimum reversal interval sufficiently long during in average zero intersect count value, comparer 1754～1756 is exported consistent signal " H " when consistent with this setting value.
Intersect the comparer that reaches the intersection count value of setting value among count value C0～C2 the earliest one of (1754～1756) and export consistent signal " H " by having imported, and it is sent to crossing detector 1751～1753 as reset pulse generally.Reset the intersection count value of crossing detector 1751～1753 thus.
As mentioned above, because any one among three threshold value Th10, Th11, the Th12 all must be represented correct (positive い) zero crossing value, must include minimum reversal interval so reach the intersection count value of setting value the earliest.And, the intersection count value that reaches setting value the earliest is used for the error computing of error-detecting portion 176.Usually, among three threshold value Th10, Th11, the Th12, the number of times that regenerated signal Sr crosses the threshold value Th10 of central authorities should be at most, reaches setting value the earliest by the intersection count value C0 of crossing detector 1752 outputs.
Turn back to Figure 25, to intersect count value C0～C2 and reset pulse and be input to error-detecting portion 176 by intersecting extraction unit 175, for the intersection count value C0 in the unit interval that makes regulation intersects count value C1 and C2 and equates substantially more than intersecting count value C1, C2 and making, error-detecting portion 176 produces the DC error signals, produces gain error signal simultaneously and makes that to intersect count value C1 and C2 with respect to intersecting count value C0 be certain ratio.DC error signal and gain error signal are sent out supply gain control circuit 174.Gain control circuit 174 carries out gain control according to gain error signal to ATC circuit 172.Thus, the output of ATC circuit 172 is controlled as so that short reversal interval signal becomes certain size.
The flow process of use Figure 28 further specifies the action of error-detecting portion 176.Among Figure 28, judge at step S301 whether the reset pulse by 175 inputs of intersection extraction unit has reached " H "; Whether reached " H " if be judged to be, judge intersecting count value C0 at step S302 is C0 〉=C1 and C0 〉=C2 with the relation of count value C1, C2 of intersecting.When satisfying this and concerning, mean that regenerated signal is in original amplitude range.
In addition, whether judge intersection count value C1, C2 greater than setting, during greater than setting, export the gain error signal that the amplitude that is judged to be regenerated signal reduces the direction of gain greatly at step S304 at step S303.In addition, so-called setting is to consider The noise and be made as and intersect 70% the value of count value C0.
On the other hand, at step S303 intersection count value C1, when C2 is not more than setting, whether judge intersect count value C1, C2 less than setting at step S305, and during less than setting, it is little and improve the gain error signal of the direction of gain to be judged to be the amplitude of regenerated signal in step S306 output.At step S302 is not under the situation of C0 〉=C1 and C0 〉=C2, and intersects count value C1, C2 at step S305 and be not less than under the situation of setting, in step S307 output gain error signal not.
According to above processing, under the situation of the waveform shown in Figure 29 A, shown in Figure 29 B, be the certain size of cardinal principle by gain control as the amplitude of short-period regenerated signal of short reversal interval signal as an example regenerated signal.Envelope detection portion 177 is detected by the envelope La of the upside of the regenerated signal shown in Figure 29 B of gain control circuit 174 outputs and the envelope Lb of downside.The same with first embodiment, filtering portion 178 according to make object lens 7 along optical axis direction only move from the focus point position+during α by the 177 detected envelope La of envelope detection portion, Lb, obtain the amplitude Ga of regenerated signal, according to make object lens 7 along optical axis direction only move from the focus point position-during α by the 177 detected envelope La of envelope detection portion, Lb, obtain the amplitude Gb of regenerated signal.
In addition, aberration adjustment part 179 is error amount control aberration correction portion 6 with (Ga-Gb) and makes the dispersion angle of the laser of injecting to object lens 7 or convergent angle change the spherical aberration of revising focal point 15.
According to the 7th embodiment, carry out gain control so that it becomes certain substantially size by amplitude to short-period regenerated signal, just can clearly macrocyclic regenerated signal and short-period regenerated signal be separated, correctly detect envelope La, Lb and amplitude Ga, the Gb of macrocyclic regenerated signal.Therefore, this embodiment has with the wave shape equalization of carrying out of the 5th embodiment and handles equal advantage.In addition, in the 7th embodiment, because needn't use the PLL circuit, so even do not implementing under the situation of tracking servo, also can obtain correct aberration correction data, amplitude Ga, Gb come down to peak swing.
According to the 7th embodiment, no matter how the condition of CD 11 can both revise aberration, make object lens 7 before and after the focal position only under the state of the α of mobile equivalent only by obtaining the control data of aberration correction portion 6 as peak swing Ga, the Gb of specific part in the regenerated signal of obtaining random signal, therefore compare with the aberration modification method of patent documentation 1 record, can finish the aberration correction with the extremely short time.
＜the eight embodiment 〉
The one-piece construction of the 8th embodiment is identical with first embodiment that Fig. 5 illustrated, but aberration Correction and Control portion and Fig. 6, Figure 12, Figure 16, Figure 19, Figure 21, Figure 24, aberration Correction and Control portion shown in Figure 25 are different.The aberration Correction and Control 10a8 of portion of the 8th embodiment is characterised in that and is arranged on servo circuit 10 inside, and the lifting capacity of obtaining when carrying out wave shape equalization in the signal Processing of optical disc apparatus is carried out the aberration correction as control data.It is identical to revise aberration this point and first～the 7th embodiment in the random signal of regenerative recording on CD 11.
In Figure 30, signal processing circuit possesses wave shape equalization portion (lifting capacity computing circuit) 201, wave shape equalization portion 201 sets lifting capacity in order to adapt to the gain that improves the little signal frequency domain of amplitude because of the characteristic of the different regenerated signal of CD, by adjusting the transmission characteristic of signal, after signal processing in do not produce error.The lifting capacity that is obtained by wave shape equalization portion 201 is sent to the aberration Correction and Control 10a8 of portion in the servo circuit 10.
What Figure 31 represented is the aberration revision program of the 8th embodiment.The step S401 of Figure 31～S407 is the same with step S101～S107 of Fig. 9, only the later program of description of step S407.In Figure 31, begin regenerative recording information at step S407, in the focus point position of step S408 servo circuit 10 objective lens 7.Then, at step S409 servo circuit 10 object lens 7 are only moved+α from the focus point position along optical axis direction.At the lifting capacity Ba of the step S410 aberration Correction and Control 10a8 of portion detection from wave shape equalization portion 201.
And, make object lens 7 only move a α from the focus point position along optical axis direction at step S411 servo circuit 10.At the lifting capacity Bb of the step S412 aberration Correction and Control 10a8 of portion detection from wave shape equalization portion 201.
And, obtain poor (Ba-Bb) of the lifting capacity of trying to achieve at the step S413 aberration Correction and Control 10a8 of portion in each position of object lens 7, judge the absolute value of this difference at step S414 | whether Ba-Bb| is smaller or equal to the threshold value Th3 of regulation.Threshold value Th3 is the value that approaches 0 regulation.If | Ba-Bb| also is not below or equal to threshold value Th3, is that error amount control aberration correction portion 6 changes the dispersion angle of the laser of injecting to object lens 7 or convergent angle at the step S415 aberration Correction and Control 10a8 of portion with (Ba-Bb), revises the spherical aberration of focal point 15.After the processing of step S415, turn back to step S408, repeat equally.
; regenerated signal at CD 11 has under the situation of randomness because of common sweep length restriction; when the thickness t of the transparency carrier 13 of CD 11 surpasses permissible range and when producing spherical aberration; as mentioned above, each peak swing of long period and short-period regenerated signal is pressed the relationship change shown in Figure 15 A～Figure 15 C for the focus deviation of object lens 7.On the other hand, the lifting capacity of wave shape equalization portion 201 is the controlling values that are used to improve the gain balance waveform of the little signal frequency domain of amplitude, and short-period signal is for the big increase of amplitude ratio hour lifting capacity of macrocyclic signal, otherwise lifting capacity reduces.
Each state of Figure 32 A～Figure 32 C presentation graphs 15A～Figure 15 C, under each state of Figure 32 A～Figure 32 C, wave shape equalization by wave shape equalization portion 201 is handled, peak swing LA, the SA of long period and short-period each regenerated signal is shown in Figure 32 D～Figure 32 F, and be irrelevant for certain with spherical aberration or focus deviation.But it is different at Figure 32 D～Figure 32 F so to be used for making peak swing LA, SA to become certain lifting capacity Ba, Bb, and lifting capacity Ba, Bb become the value of the short-period signal of expression for the amplitude ratio of macrocyclic signal.
As mentioned above, can revise spherical aberration by poor (Ba-Bb) with lifting capacity as the control data of aberration correction portion 6, as shown in Figure 31, the 8th embodiment is revised spherical aberration with regard to poor (Ba-Bb) that is to use lifting capacity as the control data of aberration correction portion 6.
What Figure 33 A represented is the switching state of the position of object lens 7, and what Figure 33 B represented is to control the lifting capacity Ba that causes, the variation of Bb repeatedly.The Ba of Figure 33 B (1), Ba (2), Ba (3) ... and Bb (1), Bb (2), Bb (3) ... in the number of times that detects of lifting capacity Ba, the Bb of step S410, S412 of postfix notation Figure 31 of parantheses.Control repeatedly by the spherical aberration correction of being undertaken as can be known by the aberration Correction and Control 10a8 of portion, absolute value | Ba-Bb| converges to 0 substantially.
According to the 8th embodiment, the lifting capacity Ba that use is obtained by wave shape equalization portion 201, Bb can generate the control data of aberration correction portion 6, therefore the circuit structure that has the aberration Correction and Control 10a8 of portion becomes simply, and can realize the advantage of aberration correction with the structure of cheapness.
According to the 8th embodiment, no matter how the condition of CD 11 can both revise aberration, make object lens 7 before and after the focus point position only under the state of the α of mobile equivalent, only, therefore compare and to finish the aberration correction with the extremely short time with the aberration modification method of patent documentation 1 record by obtaining the control data that lifting capacity Ba, Bb obtain aberration correction portion 6.
The aberration correction of first～the 8th embodiment discussed above can be independent of the regeneration of common information signal from CD 11 or to the record of the information signal of CD 11, and only carry out the processing of aberration correction, even in the regeneration of carrying out common information signal from CD 11 or under the state of the record of the information signal of CD 11, also can carry out the processing of aberration correction.
Promptly, the regeneration of common information signal from CD 11 or can be undertaken by high speed of the real time of ratio information signal to the record of the information signal of CD 11, the datum line speed that CD 11 beguines are determined according to form is rotated quickly, is not carrying out from the regeneration of the information signal of CD 11 or is not carrying out carrying out the aberration correcting process in the time of the record of the information signal of CD 11.
Sometimes therefore the thickness t of the transparency carrier 13 of CD 11 will consider record regenerating position (track) difference because of the information signal on the CD 11 in the interior all sides and the outer circumferential side fluctuation of CD 11, and the size that spherical aberration produces also has fluctuation.In addition, when continuous recording or regeneration,, also can produce spherical aberration sometimes owing to the skew of wavelength along with temperature variation.
By cut apart the record that carries out information signal or the processing of regeneration and aberration correction by the time, can in record or regeneration, revise spherical aberration, can realize not having all the time the record regenerating of error.

Claims (20)

1. optical disc apparatus possesses the regeneration unit of the information of regenerative recording on the information recording layer of CD, it is characterized in that,
Possess:
LASER Light Source;
The aberration correction portion is by adjusting the dispersion angle or the convergent angle correction spherical aberration of the laser that described LASER Light Source sends;
Object lens carry out optically focused to described laser and form focal point on described information recording layers;
Focus control portion has and makes described object lens along the travel mechanism that the optical axis direction of described laser moves, and moves described object lens described focal point is focused on the described information recording layer;
Detecting unit, only moving described object lens under the state of ormal weight from the focus point position along first direction by described focus control portion, by the random signal with a plurality of amplitudes and a plurality of cycles of described regeneration unit regenerative recording in the arbitrary region of described information recording layer, and extract the regenerated signal or the particular amplitude in its interpolation signal of this random signal or assign to obtain first amplitude of described specific part as the particular portion of cycle portions, simultaneously, by described focus control portion described object lens are only being moved under the state of described ormal weight from the focus point position along the second direction opposite with described first direction, by the random signal with a plurality of amplitudes and a plurality of cycles of described regeneration unit regenerative recording in the arbitrary region of described information recording layer, and extract the particular amplitude in the regenerated signal of this random signal or its interpolation signal or assign to obtain second amplitude of described specific part as the particular portion of cycle portions; With
Control module is controlled the difference that described aberration correction portion makes described first amplitude and described second amplitude and is leveled off to zero.
2. optical disc apparatus according to claim 1 is characterized in that,
Possess: whether identifying unit, judgement record on described information recording layer should be by the random signal of described detecting unit regeneration; With
Record cell, do not record on described information recording layer should be by the random signal of described detecting unit regeneration the time being judged to be by described identifying unit, the random signal that will have a plurality of amplitudes and a plurality of cycles is recorded in the arbitrary region of described information recording layer.
3. optical disc apparatus according to claim 2 is characterized in that,
Described zone arbitrarily is the OPC zone.
4. according to the described optical disc apparatus of claim 1, it is characterized in that,
Described detecting unit is that described specific part is carried out the envelope detection portion that described first amplitude and second amplitude are obtained in envelope detection.
5. optical disc apparatus possesses the regeneration unit of the information of regenerative recording on the information recording layer of CD, it is characterized in that,
Possess:
LASER Light Source;
The aberration correction portion is by adjusting the dispersion angle or the convergent angle correction spherical aberration of the laser that described LASER Light Source sends;
Object lens carry out optically focused to described laser and form focal point on described information recording layers;
Focus control portion has and makes described object lens along the travel mechanism that the optical axis direction of described laser moves, and moves described object lens described focal point is focused on the described information recording layer;
Detecting unit, only moving described object lens under the state of ormal weight from the focus point position along first direction by described focus control portion, by the random signal with a plurality of amplitudes and a plurality of cycles of described regeneration unit regenerative recording in the arbitrary region of described information recording layer, and extract the regenerated signal of this random signal or first particular amplitude in its interpolation signal or as the amplitude of first specific part of cycle portions and second specific part or assign to obtain first difference value of the amplitude of the amplitude of described first specific part and described second specific part as second particular portion of cycle portions, simultaneously, by described focus control portion described object lens are only being moved under the state of described ormal weight from the focus point position along the second direction opposite with described first direction, by the random signal with a plurality of amplitudes and a plurality of cycles of described regeneration unit regenerative recording in the arbitrary region of described information recording layer, and extract in the regenerated signal of this random signal or its interpolation signal the 3rd particular amplitude or as the 3rd specific part of cycle portions and the 4th particular amplitude or assign to obtain second difference value of the amplitude of the amplitude of described the 3rd specific part and described the 4th specific part as the 4th particular portion of cycle portions; With
Control module is controlled the difference that described aberration correction portion makes described first difference value and described second difference value and is leveled off to zero.
6. according to the described optical disc apparatus of claim 5, it is characterized in that,
Have:
Whether identifying unit, judgement record on described information recording layer should be by the random signal of described detecting unit regeneration; With
Record cell, do not record on described information recording layer should be by the random signal of described detecting unit regeneration the time being judged to be by described identifying unit, the random signal that will have a plurality of amplitudes and a plurality of cycles is recorded in the arbitrary region of described information recording layer.
7. according to the described optical disc apparatus of claim 6, it is characterized in that,
Described arbitrary region is the OPC zone.
8. according to the described optical disc apparatus of claim 5, it is characterized in that,
Described detecting unit has:
The zero cross detection unit detects the zero cross point that the regenerated signal of described random signal or its interpolation signal and predefined zero level intersect;
Time interval detecting unit detects the time interval between two adjacent zero cross points; With
Extraction unit is according to extracting described first～the 4th specific part by the described detected time interval of time interval detecting unit.
9. according to the described optical disc apparatus of claim 5, it is characterized in that,
Described detecting unit has:
The zero cross detection unit detects the zero cross point that the regenerated signal of described random signal or its interpolation signal and predefined zero level intersect;
Local acknowledgement's judgement unit, use regenerated signal or its interpolation signal of detected zero cross point in described zero cross detection unit and described random signal, according to the state transition decision that determines by sweep length restriction and local response characteristic and the regenerated signal or the relative desired value of its interpolation signal sampling spot separately of described random signal; With
Extraction unit is according to extracting described first～the 4th specific part by the desired value of described local acknowledgement judgement unit decision.
10. optical disc apparatus possesses the regeneration unit of the information of regenerative recording on the information recording layer of CD, it is characterized in that,
Possess:
LASER Light Source;
The aberration correction portion is by adjusting the dispersion angle or the convergent angle correction spherical aberration of the laser that described LASER Light Source sends;
Object lens carry out optically focused to described laser and form focal point on described information recording layers;
Focus control portion has and makes described object lens along the travel mechanism that the optical axis direction of described laser moves, and moves described object lens described focal point is focused on the described information recording layer;
Wave shape equalization portion carries out wave shape equalization to setting lifting capacity by the regenerated signal of the recorded information of described regeneration unit regenerative recording on described information recording layer;
Detecting unit, only moving described object lens under the state of ormal weight from the focus point position along first direction by described focus control portion, to in the arbitrary region that is recorded in described information recording layer of having regenerated by described regeneration unit have the random signal in a plurality of amplitudes and a plurality of cycles the time first lifting capacity of described wave shape equalization portion detect, simultaneously, by described focus control portion described object lens are only being moved under the state of described ormal weight from the focus point position along the second direction opposite with described first direction, in the arbitrary region that is recorded in described information recording layer of having regenerated by described regeneration unit have the random signal in a plurality of amplitudes and a plurality of cycles the time second lifting capacity of described wave shape equalization portion detect; With
Control module is controlled the difference that described aberration correction portion makes described first lifting capacity and described second lifting capacity and is leveled off to zero.
11. an aberration modification method that is used for optical disc apparatus is characterized in that,
Comprise the steps:
Regeneration step, regenerative recording the random signal in the arbitrary region of described information recording layer with a plurality of amplitudes and a plurality of cycles;
Focus steps moves the laser convergence that LASER Light Source is sent forms focal point on described information recording layer object lens along optical axis direction, and described focal point is focused on the described information recording layer;
First detects step, moved the described random signal of regeneration under the state of ormal weight in the focus point position that described object lens are focused into from described focus steps along the first direction of optical axis, extracted the regenerated signal or the particular amplitude in its interpolation signal of this random signal or assign to obtain first amplitude of described specific part as the particular portion of cycle portions;
Second detects step, only moved the described random signal of regeneration under the state of described ormal weight in focus point position that described object lens are focused into from described focus steps along the second direction opposite, extracted the regenerated signal or the particular amplitude in its interpolation signal of this random signal or assign to obtain second amplitude of described specific part as the particular portion of cycle portions with described first direction; With
Controlled step, control dispersion angle or the convergent angle aberration correction portion of revising spherical aberration by adjusting described laser makes the difference of described first amplitude and described second amplitude level off to zero.
12. the aberration modification method that is used for optical disc apparatus according to claim 11 is characterized in that,
Prime step in described regeneration step comprises following steps:
Determination step judges whether record and detect the random signal that step and second detects step regeneration described first on described information recording layer; With
Recording step, be judged to be by described determination step in that do not record on the described information recording layer should be when described first detects step and second and detect the random signal of step regeneration, the random signal that will have a plurality of amplitudes and a plurality of cycles is recorded in the arbitrary region of described information recording layer.
13. the aberration modification method that is used for optical disc apparatus according to claim 12 is characterized in that,
Described arbitrary region is the OPC zone.
14. the aberration modification method that is used for optical disc apparatus according to claim 11 is characterized in that,
It is that described specific part is carried out the envelope detection step that described first and second amplitudes are obtained in envelope detection that the described first detection step and second detects step.
15. an aberration modification method that is used for optical disc apparatus is characterized in that,
Comprise the steps:
Regeneration step, regenerative recording the random signal in the arbitrary region of described information recording layer with a plurality of amplitudes and a plurality of cycles;
Focus steps moves the laser convergence that LASER Light Source is sent forms focal point on described information recording layer object lens along optical axis direction, and described focal point is focused on the described information recording layer;
First detects step, move the described random signal of regeneration under the state of ormal weight in the focus point position that described object lens are focused into from described focus steps along the first direction of optical axis, extracted the regenerated signal of this random signal or first particular amplitude in its interpolation signal or as first specific part of cycle portions and second particular amplitude or assign to obtain first difference value of the amplitude of the amplitude of described first specific part and described second specific part as second particular portion of cycle portions;
Second detects step, moved the described random signal of regeneration under the state of ormal weight in focus point position that described object lens are focused into from described focus steps along the second direction opposite, extracted the regenerated signal of this random signal or the 3rd particular amplitude in its interpolation signal or as the 3rd specific part of cycle portions and the 4th particular amplitude or assign to obtain second difference value of the amplitude of the amplitude of described the 3rd specific part and described the 4th specific part as the 4th particular portion of cycle portions with described first direction; With
Controlled step, control dispersion angle or the convergent angle aberration correction portion of revising spherical aberration by adjusting described laser makes the difference of described first difference value and described second difference value level off to zero.
16. the aberration modification method that is used for optical disc apparatus according to claim 15 is characterized in that,
Prime step in described regeneration step comprises following steps:
Determination step judges whether record and detect the random signal that step and second detects step regeneration described first on described information recording layer; With
Recording step, be judged to be by described determination step in that do not record on the described information recording layer should be when described first detects step and second and detect the random signal of step regeneration, the random signal that will have a plurality of amplitudes and a plurality of cycles is recorded in the arbitrary region of described information recording layer.
17. the aberration modification method that is used for optical disc apparatus according to claim 16 is characterized in that,
Described arbitrary region is the OPC zone.
18. the aberration modification method that is used for optical disc apparatus according to claim 15 is characterized in that,
The described first detection step and second detects step and comprises following steps:
The zero cross detection step detects the zero cross point that the regenerated signal of described random signal or its interpolation signal and predefined zero level intersect;
The time interval is detected step, detects the time interval between two adjacent zero cross points; With
Extraction step extracts described first～the 4th specific part according to detecting the detected time interval of step in the described time interval.
19. the aberration modification method that is used for optical disc apparatus according to claim 15 is characterized in that,
The described first detection step and second detects step and comprises following steps:
The zero cross detection step detects the zero cross point that the regenerated signal of described random signal or its interpolation signal and predefined zero level intersect;
Local acknowledgement's discriminating step, use is at regenerated signal or its interpolation signal of detected zero cross point of described zero cross detection step and described random signal, according to the state transition decision that is determined by sweep length restriction and local response characteristic and the regenerated signal or the relative desired value of its interpolation signal sampling spot separately of described random signal; With
Extraction step is according to extracting described first～the 4th specific part in the desired value of described local acknowledgement discriminating step decision.
20. an aberration modification method that is used for optical disc apparatus is characterized in that,
Comprise the steps:
Regeneration step, regenerative recording the random signal in the arbitrary region of described information recording layer with a plurality of amplitudes and a plurality of cycles;
Focus steps moves the laser convergence that LASER Light Source is sent forms focal point on described information recording layer object lens along optical axis direction, and described focal point is focused on the described information recording layer;
The first wave shape equalization step, when having moved under the state of ormal weight the described random signal of regeneration along the first direction of optical axis in the focus point position that described object lens are focused into from described focus steps, the regenerated signal of described random signal is set first lifting capacity and carried out wave shape equalization;
First detects step, detects described first lifting capacity of setting in the described first wave shape equalization step;
The second wave shape equalization step, when having moved under the state of described ormal weight the described random signal of regeneration along the second direction opposite in the focus point position that described object lens are focused into from described focus steps, the regenerated signal of described random signal is set second lifting capacity and carried out wave shape equalization with described first direction;
Second detects step, detects described second lifting capacity of setting in the described second wave shape equalization step; With
Controlled step, control by adjusting described laser dispersion angle or the convergent angle aberration correction portion of revising spherical aberration that the difference of described first lifting capacity and described second lifting capacity is leveled off to is zero.
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